A broad class of proteins involved in the transport of nucleobases, NUCLEOSIDES; NUCLEOTIDES; and NUCLEIC ACIDS; across membranes.
A broad category of membrane transport proteins that specifically transport FREE FATTY ACIDS across cellular membranes. They play an important role in LIPID METABOLISM in CELLS that utilize free fatty acids as an energy source.
Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Enzymes that catalyze the formation of acyl-CoA derivatives. EC 6.2.1.
Proteins involved in the transport of nucleobases such as PYRIMIDINES and PURINES across membranes.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
Carbon-containing phosphonic acid compounds. Included under this heading are compounds that have carbon bound to either OXYGEN atom or the PHOSPHOROUS atom of the (P=O)O2 structure.
Inhibitors of reverse transcriptase (RNA-DIRECTED DNA POLYMERASE), an enzyme that synthesizes DNA on an RNA template.
Diseases of the skin with a genetic component, usually the result of various inborn errors of metabolism.
Transport proteins that carry specific substances in the blood or across cell membranes.
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
The ability of viruses to resist or to become tolerant to chemotherapeutic agents or antiviral agents. This resistance is acquired through gene mutation.
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.
Agents used to treat AIDS and/or stop the spread of the HIV infection. These do not include drugs used to treat symptoms or opportunistic infections associated with AIDS.
Purines with a RIBOSE attached that can be phosphorylated to PURINE NUCLEOTIDES.
Proteins involved in the transport of NUCLEOSIDES across cellular membranes.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Cellular proteins and protein complexes that transport amino acids across biological membranes.
Enzymes of the oxidoreductase class that catalyze the dehydrogenation of hydroxysteroids. (From Enzyme Nomenclature, 1992) EC 1.1.-.
The product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic.
Intracellular proteins that reversibly bind hydrophobic ligands including: saturated and unsaturated FATTY ACIDS; EICOSANOIDS; and RETINOIDS. They are considered a highly conserved and ubiquitously expressed family of proteins that may play a role in the metabolism of LIPIDS.
Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.

Identification of a nucleoside/nucleobase transporter from Plasmodium falciparum, a novel target for anti-malarial chemotherapy. (1/4)

Plasmodium, the aetiologic agent of malaria, cannot synthesize purines de novo, and hence depends upon salvage from the host. Here we describe the molecular cloning and functional expression in Xenopus oocytes of the first purine transporter to be identified in this parasite. This 422-residue protein, which we designate PfENT1, is predicted to contain 11 membrane-spanning segments and is a distantly related member of the widely distributed eukaryotic protein family the equilibrative nucleoside transporters (ENTs). However, it differs profoundly at the sequence and functional levels from its homologous counterparts in the human host. The parasite protein exhibits a broad substrate specificity for natural nucleosides, but transports the purine nucleoside adenosine with a considerably higher apparent affinity (K(m) 0.32+/-0.05 mM) than the pyrimidine nucleoside uridine (K(m) 3.5+/-1.1 mM). It also efficiently transports nucleobases such as adenine (K(m) 0.32+/-0.10 mM) and hypoxanthine (K(m) 0.41+/-0.1 mM), and anti-viral 3'-deoxynucleoside analogues. Moreover, it is not sensitive to classical inhibitors of mammalian ENTs, including NBMPR [6-[(4-nitrobenzyl)thio]-9-beta-D-ribofuranosylpurine, or nitrobenzylthioinosine] and the coronary vasoactive drugs, dipyridamole, dilazep and draflazine. These unique properties suggest that PfENT1 might be a viable target for the development of novel anti-malarial drugs.  (+info)

sqv-3, -7, and -8, a set of genes affecting morphogenesis in Caenorhabditis elegans, encode enzymes required for glycosaminoglycan biosynthesis. (2/4)

sqv (squashed vulva) genes comprise a set of eight independent loci in Caenorhabditis elegans required zygotically for the invagination of vulval epithelial cells and maternally for normal oocyte formation and embryogenesis. Sequencing of sqv-3, sqv-7, and sqv-8 suggested a role for the encoded proteins in glycolipid or glycoprotein biosynthesis. Using a combination of in vitro analysis of SQV enzymatic activities, sqv(+)-mediated rescue of vertebrate cell lines, and biochemical characterization of sqv mutants, we show that sqv-3, -7, and -8 all affect the biosynthesis of glycosaminoglycans and therefore compromise the function of one specific class of glycoconjugates, proteoglycans. These findings establish the importance of proteoglycans and their associated glycosaminoglycans in epithelial morphogenesis and patterning during C. elegans development.  (+info)

SQV-7, a protein involved in Caenorhabditis elegans epithelial invagination and early embryogenesis, transports UDP-glucuronic acid, UDP-N- acetylgalactosamine, and UDP-galactose. (3/4)

Caenorhabditis elegans sqv mutants are defective in vulval epithelial invagination and have a severe reduction in hermaphrodite fertility. The gene sqv-7 encodes a multitransmembrane hydrophobic protein resembling nucleotide sugar transporters of the Golgi membrane. A Golgi vesicle enriched fraction of Saccharomyces cerevisiae expressing SQV-7 transported UDP-glucuronic acid, UDP-N-acetylgalactosamine, and UDP-galactose (Gal) in a temperature-dependent and saturable manner. These nucleotide sugars are competitive, alternate, noncooperative substrates. The two mutant sqv-7 missense alleles resulted in a severe reduction of these three transport activities. SQV-7 did not transport CMP-sialic acid, GDP-fucose, UDP-N-acetylglucosamine, UDP-glucose, or GDP-mannose. SQV-7 is able to transport UDP-Gal in vivo, as shown by its ability to complement the phenotype of Madin-Darby canine kidney ricin resistant cells, a mammalian cell line deficient in UDP-Gal transport into the Golgi. These results demonstrate that unlike most nucleotide sugar transporters, SQV-7 can transport multiple distinct nucleotide sugars. We propose that SQV-7 translocates multiple nucleotide sugars into the Golgi lumen for the biosynthesis of glycoconjugates that play a pivotal role in development.  (+info)

The SQV-1 UDP-glucuronic acid decarboxylase and the SQV-7 nucleotide-sugar transporter may act in the Golgi apparatus to affect Caenorhabditis elegans vulval morphogenesis and embryonic development. (4/4)

Recent findings indicate that glycosaminoglycans can play important roles in animal development. The genes sqv-3, -7, and -8, which are necessary for vulval morphogenesis in Caenorhabditis elegans, affect the biosynthesis of chondroitin and heparan sulfate glycosaminoglycans. We cloned sqv-1 and showed that the SQV-1 protein is a type II transmembrane protein that functions as a UDP-glucuronic acid decarboxylase. SQV-1 localizes to punctate cytoplasmic compartments and colocalizes with the SQV-7 nucleotide-sugar transporter, which probably acts in the Golgi apparatus. SQV-1 and SQV-7 are both expressed in the vulva and in oocytes, where they likely act in vulval morphogenesis and embryonic development, respectively. Progeny of sqv-7 and sqv-1 null mutants fail to initiate cytokinesis, possibly because they are unable to separate the plasma membrane from the eggshell, a defect analogous to that of incomplete vulval invagination.  (+info)

1. Nucleobase: A nucleobase is one of the basic units that make up the structural components of nucleic acids, such as DNA and RNA. The four nucleobases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine.

2. Nucleoside: A nucleoside is a organic compound that consists of a nucleobase attached to a sugar molecule, either ribose or deoxyribose. The formation of a nucleoside occurs when a nucleobase links to a sugar through a beta-N-glycosidic bond. Nucleosides can be further modified by the addition of phosphate groups to form nucleotides.

3. Nucleotide: A nucleotide is a molecule composed of a nucleobase, a sugar (ribose or deoxyribose), and one or more phosphate groups. Nucleotides are the monomeric units of nucleic acids, with DNA consisting of deoxyribonucleotides and RNA consisting of ribonucleotides. The phosphate group connects to the sugar molecule through an ester bond, creating a phosphodiester linkage between nucleotides that forms the backbone of a nucleic acid polymer.

4. Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins: These proteins are responsible for the translocation of nucleobases, nucleosides, nucleotides, and/or nucleic acids across biological membranes. They facilitate the movement of these molecules between intracellular and extracellular spaces or within different cellular compartments. These transport proteins can be classified into various categories based on their structure, mechanism, and energy requirements. Examples include equilibrative nucleoside transporters (ENTs), concentrative nucleoside transporters (CNTs), nucleobase transporters, and nucleic acid transporters. Dysfunction of these transport proteins can lead to various diseases, including neurological disorders, cancer, and viral infections.

Fatty acid transport proteins (FATPs) are a group of membrane-bound proteins that play a crucial role in the uptake and transport of long-chain fatty acids across the plasma membrane of cells. They are widely expressed in various tissues, including the heart, muscle, adipose tissue, and liver.

FATPs have several domains that enable them to perform their functions, including a cytoplasmic domain that binds to fatty acids, a transmembrane domain that spans the plasma membrane, and an ATP-binding cassette (ABC) domain that hydrolyzes ATP to provide energy for fatty acid transport.

FATPs also play a role in the regulation of intracellular lipid metabolism by modulating the activity of enzymes involved in fatty acid activation, desaturation, and elongation. Mutations in FATP genes have been associated with various metabolic disorders, including congenital deficiency of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), a rare autosomal recessive disorder that affects fatty acid oxidation.

In summary, fatty acid transport proteins are essential for the uptake and metabolism of long-chain fatty acids in cells and have implications in various metabolic disorders.

A nucleoside is a biochemical molecule that consists of a pentose sugar (a type of simple sugar with five carbon atoms) covalently linked to a nitrogenous base. The nitrogenous base can be one of several types, including adenine, guanine, cytosine, thymine, or uracil. Nucleosides are important components of nucleic acids, such as DNA and RNA, which are the genetic materials found in cells. They play a crucial role in various biological processes, including cell division, protein synthesis, and gene expression.

Coenzyme A (CoA) ligases, also known as CoA synthetases, are a class of enzymes that activate acyl groups, such as fatty acids and amino acids, by forming a thioester bond with coenzyme A. This activation is an essential step in various metabolic pathways, including fatty acid oxidation, amino acid catabolism, and the synthesis of several important compounds like steroids and acetylcholine.

CoA ligases catalyze the following reaction:

acyl group + ATP + CoA ↔ acyl-CoA + AMP + PP~i~

In this reaction, an acyl group (R-) from a carboxylic acid is linked to the thiol (-SH) group of coenzyme A through a high-energy thioester bond. The energy required for this activation is provided by the hydrolysis of ATP to AMP and inorganic pyrophosphate (PP~i~).

CoA ligases are classified into three main types based on the nature of the acyl group they activate:

1. Acyl-CoA synthetases (or long-chain fatty acid CoA ligases) activate long-chain fatty acids, typically containing 12 or more carbon atoms.
2. Aminoacyl-CoA synthetases activate amino acids to form aminoacyl-CoAs, which are essential intermediates in the catabolism of certain amino acids.
3. Short-chain specific CoA ligases activate short-chain fatty acids (up to 6 carbon atoms) and other acyl groups like acetate or propionate.

These enzymes play a crucial role in maintaining cellular energy homeostasis, metabolism, and the synthesis of various essential biomolecules.

Nucleobase transport proteins are a type of membrane transport protein that facilitate the passive or active transport of nucleobases across biological membranes. Nucleobases, which include adenine, guanine, cytosine, thymine, and uracil, are fundamental components of nucleic acids (DNA and RNA) and are essential for genetic information storage, replication, and expression.

These transport proteins play a crucial role in maintaining the intracellular concentration of nucleobases by enabling their movement between intracellular and extracellular compartments or between cellular organelles. They can be specific to certain nucleobases or operate as broad-specificity transporters, depending on the protein's structure and function.

The transport process may involve uniport (transport of a single type of molecule), symport (coupled transport of multiple types of molecules in the same direction), or antiport (coupled transport of multiple types of molecules in opposite directions). The precise mechanisms governing nucleobase transport protein function are still under investigation, and further research is required to fully understand their regulation and significance in various physiological and pathophysiological contexts.

Membrane transport proteins are specialized biological molecules, specifically integral membrane proteins, that facilitate the movement of various substances across the lipid bilayer of cell membranes. They are responsible for the selective and regulated transport of ions, sugars, amino acids, nucleotides, and other molecules into and out of cells, as well as within different cellular compartments. These proteins can be categorized into two main types: channels and carriers (or pumps). Channels provide a passive transport mechanism, allowing ions or small molecules to move down their electrochemical gradient, while carriers actively transport substances against their concentration gradient, requiring energy usually in the form of ATP. Membrane transport proteins play a crucial role in maintaining cell homeostasis, signaling processes, and many other physiological functions.

Biological transport refers to the movement of molecules, ions, or solutes across biological membranes or through cells in living organisms. This process is essential for maintaining homeostasis, regulating cellular functions, and enabling communication between cells. There are two main types of biological transport: passive transport and active transport.

Passive transport does not require the input of energy and includes:

1. Diffusion: The random movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached.
2. Osmosis: The diffusion of solvent molecules (usually water) across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
3. Facilitated diffusion: The assisted passage of polar or charged substances through protein channels or carriers in the cell membrane, which increases the rate of diffusion without consuming energy.

Active transport requires the input of energy (in the form of ATP) and includes:

1. Primary active transport: The direct use of ATP to move molecules against their concentration gradient, often driven by specific transport proteins called pumps.
2. Secondary active transport: The coupling of the movement of one substance down its electrochemical gradient with the uphill transport of another substance, mediated by a shared transport protein. This process is also known as co-transport or counter-transport.

Adenine is a purine nucleotide base that is a fundamental component of DNA and RNA, the genetic material of living organisms. In DNA, adenine pairs with thymine via double hydrogen bonds, while in RNA, it pairs with uracil. Adenine is essential for the structure and function of nucleic acids, as well as for energy transfer reactions in cells through its role in the formation of adenosine triphosphate (ATP), the primary energy currency of the cell.

Organophosphonates are a class of organic compounds characterized by the presence of a carbon-phosphorus bond. They contain a phosphonic acid group, which consists of a phosphorus atom bonded to four oxygen or nitrogen atoms, with one of those bonds being replaced by a carbon atom.

In a medical context, organophosphonates are commonly used as radiopharmaceuticals in diagnostic nuclear medicine procedures, such as bone scans. These compounds have the ability to bind to hydroxyapatite, the mineral component of bones, and can be labeled with radioactive isotopes for imaging purposes. They may also be used in therapeutic settings, including as treatments for conditions such as tumor-induced hypercalcemia and Paget's disease of bone.

It is important to note that organophosphonates are distinct from organophosphates, another class of compounds that contain a phosphorus atom bonded to three oxygen or sulfur atoms and one carbon atom. Organophosphates have been widely used as pesticides and chemical warfare agents, and can pose significant health risks due to their toxicity.

Reverse Transcriptase Inhibitors (RTIs) are a class of antiretroviral drugs that are primarily used in the treatment and management of HIV (Human Immunodeficiency Virus) infection. They work by inhibiting the reverse transcriptase enzyme, which is essential for the replication of HIV.

HIV is a retrovirus, meaning it has an RNA genome and uses a unique enzyme called reverse transcriptase to convert its RNA into DNA. This process is necessary for the virus to integrate into the host cell's genome and replicate. Reverse Transcriptase Inhibitors interfere with this process by binding to the reverse transcriptase enzyme, preventing it from converting the viral RNA into DNA.

RTIs can be further divided into two categories: nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). NRTIs are analogs of the building blocks of DNA, which get incorporated into the growing DNA chain during replication, causing termination of the chain. NNRTIs bind directly to the reverse transcriptase enzyme, causing a conformational change that prevents it from functioning.

By inhibiting the reverse transcriptase enzyme, RTIs can prevent the virus from replicating and reduce the viral load in an infected individual, thereby slowing down the progression of HIV infection and AIDS (Acquired Immunodeficiency Syndrome).

Genetic skin diseases are a group of disorders caused by mutations or alterations in the genetic material (DNA), which can be inherited from one or both parents. These mutations affect the structure, function, or development of the skin and can lead to various conditions with different symptoms, severity, and prognosis.

Some examples of genetic skin diseases include:

1. Epidermolysis Bullosa (EB): A group of disorders characterized by fragile skin and mucous membranes that blister and tear easily, leading to painful sores and wounds. There are several types of EB, each caused by mutations in different genes involved in anchoring the epidermis to the dermis.
2. Ichthyosis: A family of genetic disorders characterized by dry, thickened, scaly, or rough skin. The severity and symptoms can vary widely, depending on the specific type and underlying genetic cause.
3. Neurofibromatosis: A group of conditions caused by mutations in the NF1 gene, which regulates cell growth and division. The most common types, NF1 and NF2, are characterized by the development of benign tumors called neurofibromas on the skin and nerves, as well as other symptoms affecting various organs and systems.
4. Tuberous Sclerosis Complex (TSC): A genetic disorder caused by mutations in the TSC1 or TSC2 genes, which control cell growth and division. TSC is characterized by the development of benign tumors in multiple organs, including the skin, brain, heart, kidneys, and lungs.
5. Xeroderma Pigmentosum (XP): A rare genetic disorder caused by mutations in genes responsible for repairing DNA damage from ultraviolet (UV) radiation. People with XP are extremely sensitive to sunlight and have a high risk of developing skin cancer and other complications.
6. Incontinentia Pigmenti (IP): A genetic disorder that affects the development and growth of skin, hair, nails, teeth, and eyes. IP is caused by mutations in the IKBKG gene and primarily affects females.
7. Darier's Disease: An inherited skin disorder characterized by greasy, crusted, keratotic papules and plaques, usually located on the trunk, scalp, and seborrheic areas of the body. Darier's disease is caused by mutations in the ATP2A2 gene.

These are just a few examples of genetic skin disorders. There are many more, each with its unique set of symptoms, causes, and treatments. If you or someone you know has a genetic skin disorder, it is essential to consult with a dermatologist or other healthcare professional for proper diagnosis and treatment.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Fatty acids are carboxylic acids with a long aliphatic chain, which are important components of lipids and are widely distributed in living organisms. They can be classified based on the length of their carbon chain, saturation level (presence or absence of double bonds), and other structural features.

The two main types of fatty acids are:

1. Saturated fatty acids: These have no double bonds in their carbon chain and are typically solid at room temperature. Examples include palmitic acid (C16:0) and stearic acid (C18:0).
2. Unsaturated fatty acids: These contain one or more double bonds in their carbon chain and can be further classified into monounsaturated (one double bond) and polyunsaturated (two or more double bonds) fatty acids. Examples of unsaturated fatty acids include oleic acid (C18:1, monounsaturated), linoleic acid (C18:2, polyunsaturated), and alpha-linolenic acid (C18:3, polyunsaturated).

Fatty acids play crucial roles in various biological processes, such as energy storage, membrane structure, and cell signaling. Some essential fatty acids cannot be synthesized by the human body and must be obtained through dietary sources.

Drug resistance, viral, refers to the ability of a virus to continue replicating in the presence of antiviral drugs that are designed to inhibit or stop its growth. This occurs when the virus mutates and changes its genetic makeup in such a way that the drug can no longer effectively bind to and inhibit the function of its target protein, allowing the virus to continue infecting host cells and causing disease.

Viral drug resistance can develop due to several factors, including:

1. Mutations in the viral genome that alter the structure or function of the drug's target protein.
2. Changes in the expression levels or location of the drug's target protein within the virus-infected cell.
3. Activation of alternative pathways that allow the virus to replicate despite the presence of the drug.
4. Increased efflux of the drug from the virus-infected cell, reducing its intracellular concentration and effectiveness.

Viral drug resistance is a significant concern in the treatment of viral infections such as HIV, hepatitis B and C, herpes simplex virus, and influenza. It can lead to reduced treatment efficacy, increased risk of treatment failure, and the need for more toxic or expensive drugs. Therefore, it is essential to monitor viral drug resistance during treatment and adjust therapy accordingly to ensure optimal outcomes.

Nucleotides are the basic structural units of nucleic acids, such as DNA and RNA. They consist of a nitrogenous base (adenine, guanine, cytosine, thymine or uracil), a pentose sugar (ribose in RNA and deoxyribose in DNA) and one to three phosphate groups. Nucleotides are linked together by phosphodiester bonds between the sugar of one nucleotide and the phosphate group of another, forming long chains known as polynucleotides. The sequence of these nucleotides determines the genetic information carried in DNA and RNA, which is essential for the functioning, reproduction and survival of all living organisms.

Peptide Nucleic Acids (PNAs) are synthetic, artificially produced molecules that have a structure similar to both peptides (short chains of amino acids) and nucleic acids (DNA and RNA). They consist of repeating units called "monomers" made up of a pseudopeptide backbone with nucleobases attached. The backbone is composed of N-(2-aminoethyl)glycine units, which replace the sugar-phosphate backbone found in natural nucleic acids.

PNAs are known for their high binding affinity and sequence-specific recognition of DNA and RNA molecules. They can form stable complexes with complementary DNA or RNA strands through Watson-Crick base pairing, even under conditions where normal nucleic acid hybridization is poor. This property makes them valuable tools in molecular biology for various applications such as:

1. Gene regulation and silencing
2. Antisense and antigen technologies
3. Diagnostics and biosensors
4. Study of protein-DNA interactions
5. DNA repair and mutation analysis

However, it is important to note that Peptide Nucleic Acids are not naturally occurring molecules; they are entirely synthetic and must be produced in a laboratory setting.

Anti-HIV agents are a class of medications specifically designed to treat HIV (Human Immunodeficiency Virus) infection. These drugs work by interfering with various stages of the HIV replication cycle, preventing the virus from infecting and killing CD4+ T cells, which are crucial for maintaining a healthy immune system.

There are several classes of anti-HIV agents, including:

1. Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs): These drugs act as faulty building blocks that the virus incorporates into its genetic material, causing the replication process to halt. Examples include zidovudine (AZT), lamivudine (3TC), and tenofovir.
2. Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs): These medications bind directly to the reverse transcriptase enzyme, altering its shape and preventing it from functioning properly. Examples include efavirenz, nevirapine, and rilpivirine.
3. Protease Inhibitors (PIs): These drugs target the protease enzyme, which is responsible for cleaving viral polyproteins into functional components. By inhibiting this enzyme, PIs prevent the formation of mature, infectious virus particles. Examples include atazanavir, darunavir, and lopinavir.
4. Integrase Strand Transfer Inhibitors (INSTIs): These medications block the integrase enzyme, which is responsible for inserting the viral genetic material into the host cell's DNA. By inhibiting this step, INSTIs prevent the virus from establishing a permanent infection within the host cell. Examples include raltegravir, dolutegravir, and bictegravir.
5. Fusion/Entry Inhibitors: These drugs target different steps of the viral entry process, preventing HIV from infecting CD4+ T cells. Examples include enfuvirtide (T-20), maraviroc, and ibalizumab.
6. Post-Attachment Inhibitors: This class of medications prevents the virus from attaching to the host cell's receptors, thereby inhibiting infection. Currently, there is only one approved post-attachment inhibitor, fostemsavir.

Combination therapy using multiple classes of antiretroviral drugs has been shown to effectively suppress viral replication and improve clinical outcomes in people living with HIV. Regular adherence to the prescribed treatment regimen is crucial for maintaining an undetectable viral load and reducing the risk of transmission.

Purine nucleosides are fundamental components of nucleic acids, which are the genetic materials found in all living organisms. A purine nucleoside is composed of a purine base (either adenine or guanine) linked to a sugar molecule, specifically ribose in the case of purine nucleosides.

The purine base and sugar moiety are joined together through a glycosidic bond at the 1' position of the sugar. These nucleosides play crucial roles in various biological processes, including energy transfer, signal transduction, and as precursors for the biosynthesis of DNA and RNA.

In the human body, purine nucleosides can be derived from the breakdown of endogenous nucleic acids or through the dietary intake of nucleoproteins. They are further metabolized to form uric acid, which is eventually excreted in the urine. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals and contribute to the development of gout or kidney stones.

Nucleoside transport proteins (NTTs) are membrane-bound proteins responsible for the facilitated diffusion of nucleosides and related deoxynucleosides across the cell membrane. These proteins play a crucial role in the uptake of nucleosides, which serve as precursors for DNA and RNA synthesis, as well as for the salvage of nucleotides in the cell.

There are two main types of NTTs: concentrative (or sodium-dependent) nucleoside transporters (CNTs) and equilibrative (or sodium-independent) nucleoside transporters (ENTs). CNTs mainly facilitate the uptake of nucleosides against a concentration gradient, using the energy derived from the sodium ion gradient. In contrast, ENTs mediate bidirectional transport, allowing for the equalization of intracellular and extracellular nucleoside concentrations.

Nucleoside transport proteins have been identified in various organisms, including humans, and are involved in numerous physiological processes, such as cell proliferation, differentiation, and survival. Dysregulation of NTTs has been implicated in several pathological conditions, including cancer and viral infections, making them potential targets for therapeutic intervention.

Biological transport, active is the process by which cells use energy to move materials across their membranes from an area of lower concentration to an area of higher concentration. This type of transport is facilitated by specialized proteins called transporters or pumps that are located in the cell membrane. These proteins undergo conformational changes to physically carry the molecules through the lipid bilayer of the membrane, often against their concentration gradient.

Active transport requires energy because it works against the natural tendency of molecules to move from an area of higher concentration to an area of lower concentration, a process known as diffusion. Cells obtain this energy in the form of ATP (adenosine triphosphate), which is produced through cellular respiration.

Examples of active transport include the uptake of glucose and amino acids into cells, as well as the secretion of hormones and neurotransmitters. The sodium-potassium pump, which helps maintain resting membrane potential in nerve and muscle cells, is a classic example of an active transporter.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Amino acid transport systems refer to the various membrane transport proteins that are responsible for the active or passive translocation of amino acids across cell membranes in the body. These transport systems play a crucial role in maintaining amino acid homeostasis within cells and regulating their availability for protein synthesis, neurotransmission, and other physiological processes.

There are several distinct amino acid transport systems, each with its own specificity for particular types of amino acids or related molecules. These systems can be classified based on their energy requirements, substrate specificity, and membrane localization. Some of the major amino acid transport systems include:

1. System A - This is a sodium-dependent transport system that primarily transports small, neutral amino acids such as alanine, serine, and proline. It has several subtypes (ASC, A, and AN) with different substrate affinities and kinetic properties.
2. System L - This is a sodium-independent transport system that transports large, neutral amino acids such as leucine, isoleucine, valine, phenylalanine, and tryptophan. It has several subtypes (L1, L2, and y+L) with different substrate specificities and transport mechanisms.
3. System B0 - This is a sodium-dependent transport system that transports both neutral and basic amino acids such as arginine, lysine, and ornithine. It has several subtypes (B0,+, B0-, and b0,+) with different substrate affinities and kinetic properties.
4. System y+ - This is a sodium-independent transport system that transports primarily basic amino acids such as arginine, lysine, and ornithine. It has several subtypes (y+L, y+, b0,+) with different substrate specificities and transport mechanisms.
5. System X-AG - This is a sodium-independent antiporter system that exchanges glutamate and aspartate for neutral amino acids such as cystine, serine, and threonine. It plays an essential role in maintaining redox homeostasis by regulating the intracellular levels of cysteine, a precursor of glutathione.

These transport systems are critical for maintaining cellular homeostasis and regulating various physiological processes such as protein synthesis, neurotransmission, and immune function. Dysregulation of these transport systems has been implicated in several diseases, including cancer, neurological disorders, and cardiovascular disease. Therefore, understanding the molecular mechanisms underlying these transport systems is essential for developing novel therapeutic strategies to treat these conditions.

Hydroxysteroid dehydrogenases (HSDs) are a group of enzymes that play a crucial role in steroid hormone metabolism. They catalyze the oxidation and reduction reactions of hydroxyl groups on the steroid molecule, which can lead to the activation or inactivation of steroid hormones. HSDs are involved in the conversion of various steroids, including sex steroids (e.g., androgens, estrogens) and corticosteroids (e.g., cortisol, cortisone). These enzymes can be found in different tissues throughout the body, and their activity is regulated by various factors, such as hormones, growth factors, and cytokines. Dysregulation of HSDs has been implicated in several diseases, including cancer, diabetes, and cardiovascular disease.

Taurocholic acid is a bile salt, which is a type of organic compound that plays a crucial role in the digestion and absorption of fats and fat-soluble vitamins in the small intestine. It is formed in the liver by conjugation of cholic acid with taurine, an amino sulfonic acid.

Taurocholic acid has a detergent-like effect on the lipids in our food, helping to break them down into smaller molecules that can be absorbed through the intestinal wall and transported to other parts of the body for energy production or storage. It also helps to maintain the flow of bile from the liver to the gallbladder and small intestine, where it is stored until needed for digestion.

Abnormal levels of taurocholic acid in the body have been linked to various health conditions, including gallstones, liver disease, and gastrointestinal disorders. Therefore, it is important to maintain a healthy balance of bile salts, including taurocholic acid, for optimal digestive function.

Fatty acid-binding proteins (FABPs) are a group of small intracellular proteins that play a crucial role in the transport and metabolism of fatty acids within cells. They are responsible for binding long-chain fatty acids, which are hydrophobic molecules, and facilitating their movement across the cell while protecting the cells from lipotoxicity.

FABPs are expressed in various tissues, including the heart, liver, muscle, and brain, with different isoforms found in specific organs. These proteins have a high affinity for long-chain fatty acids and can regulate their intracellular concentration by controlling the uptake, storage, and metabolism of these molecules.

FABPs also play a role in modulating cell signaling pathways that are involved in various physiological processes such as inflammation, differentiation, and apoptosis. Dysregulation of FABP expression and function has been implicated in several diseases, including diabetes, obesity, cancer, and neurodegenerative disorders.

In summary, fatty acid-binding proteins are essential intracellular proteins that facilitate the transport and metabolism of long-chain fatty acids while regulating cell signaling pathways.

Antiviral agents are a class of medications that are designed to treat infections caused by viruses. Unlike antibiotics, which target bacteria, antiviral agents interfere with the replication and infection mechanisms of viruses, either by inhibiting their ability to replicate or by modulating the host's immune response to the virus.

Antiviral agents are used to treat a variety of viral infections, including influenza, herpes simplex virus (HSV) infections, human immunodeficiency virus (HIV) infection, hepatitis B and C, and respiratory syncytial virus (RSV) infections.

These medications can be administered orally, intravenously, or topically, depending on the type of viral infection being treated. Some antiviral agents are also used for prophylaxis, or prevention, of certain viral infections.

It is important to note that antiviral agents are not effective against all types of viruses and may have significant side effects. Therefore, it is essential to consult with a healthcare professional before starting any antiviral therapy.

Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins*Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ... Membrane Transport Proteins [D12.776.157.530]. *Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins [ ... Membrane Transport Proteins [D12.776.543.585]. *Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins [ ... "Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins" is a descriptor in the National Library of Medicines ...
"Physiological and pharmacological roles of nucleoside transporter proteins". Nucleosides, Nucleotides & Nucleic Acids. 27 (6): ... are transport proteins that are specific to nucleosides and nucleobases, and are part of the major facilitator superfamily. ... Protein families, Membrane proteins, Transmembrane proteins, Transmembrane transporters, Transport proteins, Integral membrane ... In humans ENT are also known as SLC29, a group of plasmalemmal transport proteins which transport nucleoside substrates like ...
The two nucleic acids, DNA and RNA, are polymers of nucleotides. Each nucleotide is composed of a phosphate attached to a ... The amino acids or sugars released by these extracellular enzymes are then pumped into cells by active transport proteins. ... Individual nucleosides are made by attaching a nucleobase to a ribose sugar. These bases are heterocyclic rings containing ... amino acids can be linked in varying sequences to form a huge variety of proteins. Proteins are made from amino acids that have ...
nucleobase, nucleoside, nucleotide and nucleic acid metabolic process. nucleobase, nucleoside and nucleotide metabolic process ... "Global analysis of protein localization in budding yeast." Nature 425:686-691.14562095 ... Involved in nucleotide binding. Specific Function. This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with ... "The nucleotide sequence of Saccharomyces cerevisiae chromosome IV." Nature 387:75-78.9169867 ...
Monosaccharide Transport Proteins. Neurotransmitter Transport Proteins. Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ...
... intracellular transport;3.24653339861932e-32!GO:0006139;nucleobase, nucleoside, nucleotide and nucleic acid metabolic process; ... cotranslational protein targeting to membrane;1.49521560624738e-05!GO:0015931;nucleobase, nucleoside, nucleotide and nucleic ... proton transport;0.00323372532820864!GO:0045934;negative regulation of nucleobase, nucleoside, nucleotide and nucleic acid ... positive regulation of nucleobase, nucleoside, nucleotide and nucleic acid metabolic process;0.0304578247524085!GO:0045185; ...
Nucleotide, and Nucleic Acid Transport Proteins [D12.776.157.530.625] Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ... Nucleotide, and Nucleic Acid Transport Proteins [D12.776.543.585.625] Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ... Mitochondrial Precursor Protein Import Complex Proteins [D12.776.575.750.594] Mitochondrial Precursor Protein Import Complex ... Mitochondrial Precursor Protein Import Complex Proteins [D12.776.543.585.475.594] Mitochondrial Precursor Protein Import ...
nucleobase, nucleoside, nucleotide and nucleic acid metabolism. 75. 1.00%. GO:0006810. transport. 74. 0.98%. ... protein transporter activity. 2. 0.03%. GO:0016209. antioxidant activity. 1. 0.01%. Total. 7530. 100.00%. Counted Terms. 768 ...
Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins [D12.776.157.530.625] * Nucleotide Transport Proteins [ ... Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid Transport Proteins [D12.776.543.585.625] * Nucleotide Transport Proteins [ ... Amino Acids, Peptides, and Proteins [D12] * Proteins [D12.776] * Carrier Proteins [D12.776.157] * Membrane Transport Proteins [ ... Amino Acids, Peptides, and Proteins [D12] * Proteins [D12.776] * Carrier Proteins [D12.776.157] * Membrane Transport Proteins [ ...
Polysaccharides are broken down into monosaccharides; lipids into fatty acids; nucleic acids into nucleotides; and proteins ... Nucleobases (nucleic acid bases) are nitrogen-based, ring-shaped molecules that comprise the cornerstones of nucleotides. ... Transport In & Out. Metabolism. Cell Intelligence. Synopsis. Genetics. Nucleic Acids. Genes. Chromosomes. Alternation of ... The adenine ring and ribose sugar form adenosine, which is a purine nucleoside. In animals, adenosine acts as a neuromodulator ...
"Primordial Emergence of a Nucleic Acid Binding Protein via Phase Separation and Statistical Ornithine-to-Arginine Conversion ... "Adsorption of Nucleotides onto Ferromagnesian Phyllosilicates: Significance for the Origin of Life" - Pedreire-Segade (2016) ... "A Prebiotic Ribosylation of Pyrimidine Nucleobases Enabled by Metal Cations and Clay Minerals" - Chen (2021) Life , Free Full- ... "A Plausible Prebiotic Path to Nucleosides: : Ribosides and Related Aldosides Generated from Ribulose, Fructose, and Similar ...
purine nucleoside binding. IEP. Neighborhood. MF. GO:0003676. nucleic acid binding. IEP. Neighborhood. ... nucleobase-containing compound metabolic process. IEP. Neighborhood. BP. GO:0006163. purine nucleotide metabolic process. IEP. ... protein localization to endoplasmic reticulum. IEP. Neighborhood. BP. GO:0071702. organic substance transport. IEP. ... glutamine family amino acid biosynthetic process. IEP. Neighborhood. BP. GO:0009116. nucleoside metabolic process. IEP. ...
tRNA aminoacylation for protein translation. IEP. Enrichment. BP. GO:0006520. cellular amino acid metabolic process. IEP. ... nucleobase-containing compound metabolic process. IEP. Enrichment. BP. GO:0006163. purine nucleotide metabolic process. IEP. ... protein-containing complex. IEP. Enrichment. CC. GO:0033178. proton-transporting two-sector ATPase complex, catalytic domain. ... purine nucleotide biosynthetic process. IEP. Enrichment. BP. GO:0006165. nucleoside diphosphate phosphorylation. IEP. ...
internal protein amino acid acetylation. IEP. Enrichment. BP. GO:0006575. cellular modified amino acid metabolic process. IEP. ... regulation of nucleic acid-templated transcription. IEP. Enrichment. BP. GO:2000112. regulation of cellular macromolecule ... cyclic-nucleotide phosphodiesterase activity. IEP. Enrichment. MF. GO:0004114. 3,5-cyclic-nucleotide phosphodiesterase ... nucleoside phosphate biosynthetic process. IEP. Enrichment. BP. GO:1901362. organic cyclic compound biosynthetic process. IEP. ...
Nucleosides Nucleotides Nucleic Acids, 2007, Volume 26, p.979-83, (2007) Transferability of fragmental contributions to the ... The use of conformationally rigid nucleoside probes to study the role of sugar pucker and nucleobase orientation in the ... On the Use of low-resolution Data to Improve Structure Prediction of Proteins and Protein Complexes, DAbramo, Marco, Meyer Tim ... Theoretical characterization of the dynamical behavior and transport properties of alpha,gamma-peptide nanotubes in solution., ...
In addition, we show that these proteins have a 5 but not apparent 3 preference for neighboring nucleotides. Our results ... Members of the mammalian AlkB family are known to mediate nucleic acid demethylation1,2. ALKBH7, a mammalian AlkB homologue, ... Since T. vaginalis is an obligate parasite that requires nucleoside salvage pathways, essential nucleoside ribohydrolase ... Compatibility of Nucleobases Containing Pt(II) Complexes with Red Blood Cells for Possible Drug Delivery Applications. ...
A nucleotide is regarded as the basic building block of nucleic acids (e.g. DNA and RNA). A nucleic acid is one of the major ... Without the phosphate group(s), the compound is referred to as a nucleoside (i.e. a nucleobase + pentose sugar) ... groups of biomolecules others are carbohydrates (especially, polysaccharides), proteins, and amino acids. Nucleic acids are ... Its functions are for intracellular energy transport for various metabolic processes including biosynthetic reactions, motility ...
Overall, this sampling analysis demonstrated that the exudation of organic acids, amino-acids and nucleobases/nucleosides, as ... L-Aspartate, together with its role in protein nucleic acid biosynthesis, can serve as a precursor for nitrogen storage ... There are two clearly correlated groups of compounds: The first group comprises nucleobases, nucleotides and amino acids while ... We also discarded transport reactions with no absolute flux value above 10-3 mmol gDW-1 h-1 in any of the environmental samples ...
Nucleic acids are the biopolymers. Nucleotides are the building blocks of DNA and RNA molecules. One of the ways proteins are ... For now, when we discuss nucleic acids are deoxyribonucleic acid are known as purine, becomes! Nucleoside by one phosphate ... This nucleotide contains the five-carbon sugar deoxyribose (at center), a nucleobase called adenine (upper right), and one ... a messenger molecule that is important in many processes including the regulation of metabolism and transporting chemical ...
Here, we assess the evolutionary potential of libraries of nucleic acids with six nucleotide building blocks as reservoirs for ... These systems have been used to direct the synthesis of artificial proteins having unnatural amino acids, in FDA-approved ... Evolved AEGISzymes with nitro-carrying nucleobase Z appear to exploit a general acid-base catalytic mechanism to cleave that ... Also recovered are nucleoside 5-diphosphates and nucleoside 5-monophosphates, both likely arising from 5-triphosphate ...
Nucleotide, and Nucleic Acid Transport Proteins [D12.776.157.530.625] Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ... Nucleotide, and Nucleic Acid Transport Proteins [D12.776.543.585.625] Nucleobase, Nucleoside, Nucleotide, and Nucleic Acid ... A highly conserved family of ATPases that facilitate the transport of lipids and cations across the plasma membrane. ... A highly conserved family of ATPases that facilitate the transport of lipids and cations across the plasma membrane. ...
ion transmembrane transport. IEP. Enrichment. BP. GO:0034654. nucleobase-containing compound biosynthetic process. IEP. ... nucleotide metabolic process. IEP. Enrichment. BP. GO:0009123. nucleoside monophosphate metabolic process. IEP. Enrichment. ... nucleic acid-templated transcription. IEP. Enrichment. MF. GO:0097747. RNA polymerase activity. IEP. Enrichment. ... ribosomal protein L7/L12 [Ensembl]. Ribosomal protein.... 0.19. OrthoFinder. AGT26518. N559_4934. 50S ribosomal protein L7/L12 ...
Nucleic acid amplification-based methods for detection of enteric viruses: definition of controls and interpretation of results ... Reactions of beta-propiolactone with nucleobase analogues, nucleosides, and peptides: Implications for the inactivation of ... SNP single-nucleotide polymorphism (single-nucleotide polymorphism)/RD RijksDriehoek (RijksDriehoek) typing of Mycobacterium ... Transplacental transport of IgG antibodies to preterm infants: a review of the literature. van den Berg J.P., Westerbeek E.A., ...
... nucleic acid binding;P:DNA replication, nucleobase, nucleoside, nucleotide and nucleic acid metabolic process;C:mitochondrion, ... sec61beta family protein. F:protein transporter activity;P:protein transport;C:unknown;MFPO. O.I.. C.G.. H.G.. Please select. ... protein amino acid dephosphorylation, N-terminal protein myristoylation, regulation of protein amino acid phosphorylation;C: ... F:protein serine/threonine kinase activity, protein kinase activity, kinase activity, ATP binding;P:protein amino acid ...
Types of nucleic acids Constituents. *Nucleobases. *Nucleosides. *Nucleotides. *Deoxynucleotides. Ribonucleic acids .mw-parser- ... The complex is bound by a motor protein and is transported to the target location (neurite extension) along the cytoskeleton. ... "Nucleic Acids Research. 34 (8): 2428-37. doi:10.1093/nar/gkl287. PMC 1458515. PMID 16682450.. ... This mature mRNA is then translated into a polymer of amino acids: a protein, as summarized in the central dogma of molecular ...
... nucleobase, nucleoside, nucleotide and nucleic acid metabolic process),GO:0006756(AMP phosphorylation),GO:0007596(blood ... nucleoside, nucleotide kinase activity),GO:0042802(identical protein binding),GO:0046899(nucleoside triphosphate adenylate ... GO:0005244(voltage-gated ion channel activity),GO:0005249(voltage-gated potassium channel activity),GO:0006811(ion transport), ... GO:0000166(nucleotide binding),GO:0004674(protein serine/threonine kinase activity),GO:0004712(protein serine/threonine/ ...
negative regulation of nucleic acid-templated transcription. IEP. Enrichment. BP. GO:2000113. negative regulation of cellular ... catalytic activity, acting on a protein. IEP. Enrichment. MF. GO:1901265. nucleoside phosphate binding. IEP. Enrichment. ... cyclic nucleotide biosynthetic process. IEP. Enrichment. BP. GO:0009890. negative regulation of biosynthetic process. IEP. ... negative regulation of nucleobase-containing compound metabolic process. IEP. Enrichment. BP. GO:0048519. negative regulation ...
Backbone FC-H···O hydrogen bonds in 2F-substituted nucleic acids., Martín-Pintado, Nerea, Deleavey Glen F., Portella Guillem, ... Conformationally rigid nucleoside probes help understand the role of sugar pucker and nucleobase orientation in the thrombin- ... Nucleotide binding switches the information flow in ras GTPases., Raimondi, Francesco, Portella Guillem, Orozco Modesto, and ... Emergence of chromatin hierarchical loops from protein disorder and nucleosome asymmetry, Sridhar, Akshay, Farr Stephen E., ...

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