A photoactivable URIDINE analog that is used as an affinity label.
Enzymes which transfer sulfur atoms to various acceptor molecules. EC 2.8.1.
The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.
Enzymes that catalyze the cleavage of a carbon-sulfur bond by means other than hydrolysis or oxidation. EC 4.4.
A transfer RNA which is specific for carrying glutamic acid to sites on the ribosomes in preparation for protein synthesis.
Uridine is a nucleoside, specifically a derivative of pyrimidine, that is composed of a uracil molecule joined to a ribose sugar molecule through a β-N1 glycosidic bond, and has significant roles in RNA synthesis, energy transfer, and cell signaling.
A transfer RNA which is specific for carrying lysine to sites on the ribosomes in preparation for protein synthesis.
The sequential set of three nucleotides in TRANSFER RNA that interacts with its complement in MESSENGER RNA, the CODON, during translation in the ribosome.
Nucleosides in which the base moiety is substituted with one or more sulfur atoms.
3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.
An enzyme that catalyzes the transfer of the planetary sulfur atom of thiosulfate ion to cyanide ion to form thiocyanate ion. EC 2.8.1.1.
A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.
Enzymes that catalyze the S-adenosyl-L-methionine-dependent methylation of ribonucleotide bases within a transfer RNA molecule. EC 2.1.1.
Occurs in seeds of Brassica and Crucifera species. Thiouracil has been used as antithyroid, coronary vasodilator, and in congestive heart failure although its use has been largely supplanted by other drugs. It is known to cause blood dyscrasias and suspected of terato- and carcinogenesis.
A pyrimidine nucleoside that is composed of the base CYTOSINE linked to the five-carbon sugar D-RIBOSE.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.
Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.

Single atom modification (O-->S) of tRNA confers ribosome binding. (1/136)

Escherichia coli tRNALysSUU, as well as human tRNALys3SUU, has 2-thiouridine derivatives at wobble position 34 (s2U*34). Unlike the native tRNALysSUU, the full-length, unmodified transcript of human tRNALys3UUU and the unmodified tRNALys3UUU anticodon stem/loop (ASLLys3UUU) did not bind AAA- or AAG-programmed ribosomes. In contrast, the completely unmodified yeast tRNAPhe anticodon stem/loop (ASLPheGAA) had an affinity (Kd = 136+/-49 nM) similar to that of native yeast tRNAPheGmAA (Kd = 103+/-19 nM). We have found that the single, site-specific substitution of s2U34 for U34 to produce the modified ASLLysSUU was sufficient to restore ribosomal binding. The modified ASLLysSUU bound the ribosome with an affinity (Kd = 176+/-62 nM) comparable to that of native tRNALysSUU (Kd = 70+/-7 nM). Furthermore, in binding to the ribosome, the modified ASLLys3SUU produced the same 16S P-site tRNA footprint as did native E. coli tRNALysSUU, yeast tRNAPheGmAA, and the unmodified ASLPheGAA. The unmodified ASLLys3UUU had no footprint at all. Investigations of thermal stability and structure monitored by UV spectroscopy and NMR showed that the dynamic conformation of the loop of modified ASLLys3SUU was different from that of the unmodified ASLLysUUU, whereas the stems were isomorphous. Based on these and other data, we conclude that s2U34 in tRNALysSUU and in other s2U34-containing tRNAs is critical for generating an anticodon conformation that leads to effective codon interaction in all organisms. This is the first example of a single atom substitution (U34-->s2U34) that confers the property of ribosomal binding on an otherwise inactive tRNA.  (+info)

Kinetics of oxidation of aliphatic and aromatic thiols by myeloperoxidase compounds I and II. (2/136)

Myeloperoxidase (MPO) is the most abundant protein in neutrophils and plays a central role in microbial killing and inflammatory tissue damage. Because most of the non-steroidal anti-inflammatory drugs and other drugs contain a thiol group, it is necessary to understand how these substrates are oxidized by MPO. We have performed transient kinetic measurements to study the oxidation of 14 aliphatic and aromatic mono- and dithiols by the MPO intermediates, Compound I (k3) and Compound II (k4), using sequential mixing stopped-flow techniques. The one-electron reduction of Compound I by aromatic thiols (e.g. methimidazole, 2-mercaptopurine and 6-mercaptopurine) varied by less than a factor of seven (between 1.39 +/- 0.12 x 10(5) M(-1) s(-1) and 9.16 +/- 1.63 x 10(5) M(-1) s(-1)), whereas reduction by aliphatic thiols was demonstrated to depend on their overall net charge and hydrophobic character and not on the percentage of thiol deprotonation or redox potential. Cysteamine, cysteine methyl ester, cysteine ethyl ester and alpha-lipoic acid showed k3 values comparable to aromatic thiols, whereas a free carboxy group (e.g. cysteine, N-acetylcysteine, glutathione) diminished k3 dramatically. The one-electron reduction of Compound II was far more constrained by the nature of the substrate. Reduction by methimidazole, 2-mercaptopurine and 6-mercaptopurine showed second-order rate constants (k4) of 1.33 +/- 0.08 x 10(5) M(-1) s(-1), 5.25 +/- 0.07 x 10(5) M(-1) s(-1) and 3.03 +/- 0.07 x 10(3) M(-1) s(-1). Even at high concentrations cysteine, penicillamine and glutathione could not reduce Compound II, whereas cysteamine (4.27 +/- 0.05 x 10(3) M(-1) s(-1)), cysteine methyl ester (8.14 +/- 0.08 x 10(3) M(-1) s(-1)), cysteine ethyl ester (3.76 +/- 0.17 x 10(3) M(-1) s(-1)) and alpha-lipoic acid (4.78 +/- 0.07 x 10(4) M(-1) s(-1)) were demonstrated to reduce Compound II and thus could be expected to be oxidized by MPO without co-substrates.  (+info)

The preparation and properties of 4-thiouridine containing 2'-5' and 3'-5' dinucleoside monophosphates. (3/136)

2'-5' and 3'-5' dinucleoside monophosphates containing 4-thiouridine were prepared by the thiolation of the cytosine containing compounds and purified by chromatography on a DEAE-Sephadex column. The chromatographic and optical properties of the isomers are compared.  (+info)

Investigation of the recognition of an important uridine in an internal loop of a hairpin ribozyme prepared using post-synthetically modified oligonucleotides. (4/136)

We introduced 4-thio- ((4S)U), 2-thio- ((2S)U), 4- O -methyluridine ((4Me)U) and cytidine substitutions for U+2, which is an important base for cleavage in a substrate RNA. Oligonucleotides containing 4-thio- and 4- O -methyluridine were prepared by a new convenient post-synthetic modification method using a 4- O - p -nitrophenyl-uridine derivative. A hairpin ribozyme cleaved the substrate RNA with either C+2, (4S)U+2 or (4Me)U+2 at approximately 14-, 6- and 4-fold lower rates, respectively, than that of the natural substrate. In contrast, the substrate with a (2S)U+2 was cleaved with the same activity as the natural substrate. These results suggest that the O4 of U+2 is involved in hydrogen bonding at loop A, but the O2 of U+2 is not recognized by the active residues. Circular dichroism data of the ribozymes containing (4S)U+2 and (2S)U+2, as well as the susceptibility of the thiocarbonyl group to hydrogen peroxide, suggest that a conformational change of U+2 occurs during the domain docking in the cleavage reaction. We propose here the conformational change of U+2 from the ground state to the active molecule during the reaction.  (+info)

Using genomic information to investigate the function of ThiI, an enzyme shared between thiamin and 4-thiouridine biosynthesis. (5/136)

The gene thiI encodes a protein (ThiI) that plays a role in the transfer of sulfur from cysteine to both thiamin and 4-thiouridine, but the reaction catalyzed by ThiI remains undetermined. Based upon sequence alignments, ThiI shares a unique "P-loop" motif with the PPi synthetase family, four enzymes that catalyze adenylation and subsequent substitution of carbonyl oxygens. To test whether or not this motif is critical for ThiI function, the Asp in the motif was converted to Ala (D189A), and a screen for in vivo 4-thiouridine production revealed the altered enzyme to be inactive. Further scrutiny of sequence data and the crystal structures of two members of the PPi synthetase family implicated Lys321 in the proposed adenylation function of ThiI, and the critical nature of Lys321 has been demonstrated by site-directed mutagenesis and genetic screening. Our results, then, indicate that ThiI catalyzes the adenylation of a substrate at the expense of ATP, a narrowing of possible reactions that provides a strong new basis for deducing the early steps in the transfer of sulfur from cysteine to both thiamin and 4-thiouridine.  (+info)

Interaction of the yeast DExH-box RNA helicase prp22p with the 3' splice site during the second step of nuclear pre-mRNA splicing. (6/136)

Using site-specific incorporation of the photo-chemical cross-linking reagent 4-thiouridine, we demonstrate the previously unknown association of two proteins with yeast 3' splice sites. One of these is an unidentified approximately 122 kDa protein that cross-links to 3' splice sites during formation of the pre--spliceosome. The other factor is the DExH-box RNA helicase, Prp22p. With substrates functional in the second step of splicing, only very weak cross-linking of Prp22p to intron sequences at the 3' splice site is observed. In contrast, substrates blocked at the second step exhibit strong cross-linking of Prp22 to intron sequences at the 3' splice site, but not to adjacent exon sequences. In vitro reconstitution experiments also show that the association of Prp22p with intron sequences at the 3' splice site is dependent on Prp16p and does not persist when release of mature mRNA from the spliceosome is blocked. Taken together, these results suggest that the 3' splice site of yeast introns is contacted much earlier than previously envisioned by a protein of approximately 120 kDa, and that a transient association of Prp22p with the 3' splice site occurs between the first and second catalytic steps.  (+info)

Evidence that ThiI, an enzyme shared between thiamin and 4-thiouridine biosynthesis, may be a sulfurtransferase that proceeds through a persulfide intermediate. (7/136)

ThiI is an enzyme common to the biosynthetic pathways leading to both thiamin and 4-thiouridine in tRNA. Comparison of the ThiI sequence with protein sequences in the data bases revealed that the Escherichia coli enzyme contains a C-terminal extension displaying sequence similarity to the sulfurtransferase rhodanese. Cys-456 of ThiI aligns with the active site cysteine residue of rhodanese that transiently forms a persulfide during catalysis. We investigated the functional importance of this sequence similarity and discovered that, like rhodanese, ThiI catalyzes the transfer of sulfur from thiosulfate to cyanide. Mutation of Cys-456 to alanine impairs this sulfurtransferase activity, and the C456A ThiI is incapable of supporting generation of 4-thiouridine in tRNA both in vitro and in vivo. We therefore conclude that Cys-456 of ThiI is critical for activity and propose that Cys-456 transiently forms a persulfide during catalysis. To accommodate this hypothesis, we propose a general mechanism for sulfur transfer in which the terminal sulfur of the persulfide first acts as a nucleophile and is then transferred as an equivalent of S(2-) rather than S(0).  (+info)

Evidence for the transfer of sulfane sulfur from IscS to ThiI during the in vitro biosynthesis of 4-thiouridine in Escherichia coli tRNA. (8/136)

IscS from Escherichia coli is a cysteine desulfurase that has been shown to be involved in Fe-S cluster formation. The enzyme converts L-cysteine to L-alanine and sulfane sulfur (S(0)) in the form of a cysteine persulfide in its active site. Recently, we reported that IscS can donate sulfur for the in vitro biosynthesis of 4-thiouridine (s(4)U), a modified nucleotide in tRNA. In addition to IscS, s(4)U synthesis in E. coli also requires the thiamin biosynthetic enzyme ThiI, Mg-ATP, and L-cysteine as the sulfur donor. We now report evidence that the sulfane sulfur generated by IscS is transferred sequentially to ThiI and then to tRNA during the in vitro synthesis of s(4)U. Treatment of ThiI with 5-((2-iodoacetamido)ethyl)-1-aminonapthalene sulfonic acid (I-AEDANS) results in irreversible inhibition, suggesting the presence of a reactive cysteine that is required for binding and/or catalysis. Both ATP and tRNA can protect ThiI from I-AEDANS inhibition. Finally, using gel shift and protease protection assays, we show that ThiI binds to unmodified E. coli tRNA(Phe). Together, these results suggest that ThiI is a recipient of S(0) from IscS and catalyzes the ultimate sulfur transfer step in the biosynthesis of s(4)U.  (+info)

Thiouridine is not a medical term per se, but it is a term used in biochemistry and genetics. Thiouridine is a modified nucleoside that contains a sulfur atom, and it is found in the RNA (ribonucleic acid) of certain organisms, including yeast and mammals.

Thiouridine can be formed through the modification of uridine, one of the four basic building blocks of RNA, by the addition of a sulfur atom from a donor molecule such as cysteine or a derivative thereof. This modification can affect the stability, structure, and function of RNA molecules, including transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs).

In medicine, thiouridine is not used as a therapeutic agent or diagnostic tool, but it may be studied in the context of genetic research or molecular biology.

Sulfurtransferases are a group of enzymes that catalyze the transfer of a sulfur group from one molecule to another. These enzymes play a crucial role in various biological processes, including the detoxification of harmful compounds and the synthesis of important metabolites. They can be found in many organisms, from bacteria to humans.

In humans, there are several types of sulfurtransferases, including cysteine conjugate beta-lyase, rhodanese, and 3'-phosphoadenosine 5'-phosphosulfate (PAPS) reductase. These enzymes have different substrates and functions, but they all share the ability to transfer a sulfur group from one molecule to another.

For example, rhodanese is an enzyme that transfers a sulfur atom from thiosulfate to cyanide, converting it to less toxic thiocyanate. This reaction is important in the detoxification of cyanide in the body.

Sulfurtransferases are also involved in the synthesis of various metabolites, such as iron-sulfur clusters and molybdenum cofactor, which are essential for the function of many enzymes.

Deficiencies or mutations in sulfurtransferase genes can lead to various diseases and disorders, highlighting their importance in human health.

Transfer RNA (tRNA) is a type of RNA molecule that plays a crucial role in protein synthesis, the process by which cells create proteins. In protein synthesis, tRNAs serve as adaptors, translating the genetic code present in messenger RNA (mRNA) into the corresponding amino acids required to build a protein.

Each tRNA molecule has a distinct structure, consisting of approximately 70-90 nucleotides arranged in a cloverleaf shape with several loops and stems. The most important feature of a tRNA is its anticodon, a sequence of three nucleotides located in one of the loops. This anticodon base-pairs with a complementary codon on the mRNA during translation, ensuring that the correct amino acid is added to the growing polypeptide chain.

Before tRNAs can participate in protein synthesis, they must be charged with their specific amino acids through an enzymatic process involving aminoacyl-tRNA synthetases. These enzymes recognize and bind to both the tRNA and its corresponding amino acid, forming a covalent bond between them. Once charged, the aminoacyl-tRNA complex is ready to engage in translation and contribute to protein formation.

In summary, transfer RNA (tRNA) is a small RNA molecule that facilitates protein synthesis by translating genetic information from messenger RNA into specific amino acids, ultimately leading to the creation of functional proteins within cells.

Carbon-sulfur lyases are a class of enzymes that catalyze the cleavage of carbon-sulfur bonds in organic compounds, resulting in the formation of a new double bond. These enzymes play important roles in various biological processes, including the metabolism of sulfur-containing amino acids and the biosynthesis of certain cofactors and secondary metabolites.

Carbon-sulfur lyases are classified under EC number 4.4.1, which includes enzymes that catalyze the formation of carbon-carbon bonds by means other than those involving oxidoreductases. Within this class, carbon-sulfur lyases are further divided into several subcategories based on their specific reaction mechanisms and substrate specificities.

One example of a carbon-sulfur lyase is cysteine desulfurase (EC 2.8.1.7), which catalyzes the formation of alanine and a persulfide group from L-cysteine, releasing elemental sulfur as a byproduct. This enzyme plays a critical role in the biosynthesis of iron-sulfur clusters, which are essential cofactors for many proteins involved in electron transfer reactions.

Another example is 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2), which catalyzes the formation of a persulfide group on a cysteine residue in the enzyme itself, using 3-mercaptopyruvate as a sulfur donor. This enzyme is involved in the biosynthesis of various secondary metabolites containing sulfur atoms, such as allicin in garlic and penicillamine in certain fungi.

Overall, carbon-sulfur lyases are important enzymes that play critical roles in various biological processes involving the cleavage or formation of carbon-sulfur bonds.

Transfer RNA (tRNA) that is specific for the amino acid glutamic acid (Glu or E) is referred to as "tRNA-Glu" or "tRNAGlu." This tRNA carries the amino acid glutamic acid to the ribosome during protein synthesis, where it gets incorporated into a growing polypeptide chain according to the genetic code.

The transfer RNA molecules are small adaptor molecules that facilitate translation of the genetic code present in messenger RNA (mRNA) into the corresponding amino acid sequence of proteins. Each tRNA has an anticodon region, which recognizes and binds to a specific codon on the mRNA through base-pairing interactions. The other end of the tRNA contains a binding site for the corresponding amino acid, ensuring that the correct amino acid is added during protein synthesis.

In summary, "tRNA-Glu" or "tRNAGlu" refers to the specific transfer RNA molecule responsible for transporting and incorporating glutamic acid into proteins during translation.

Uridine is a nucleoside that consists of a pyrimidine base (uracil) linked to a pentose sugar (ribose). It is a component of RNA, where it pairs with adenine. Uridine can also be found in various foods such as beer, broccoli, yeast, and meat. In the body, uridine can be synthesized from orotate or from the breakdown of RNA. It has several functions, including acting as a building block for RNA, contributing to energy metabolism, and regulating cell growth and differentiation. Uridine is also available as a dietary supplement and has been studied for its potential benefits in various health conditions.

I'm happy to help! Here are the definitions for each of those terms:

1. RNA (Ribonucleic Acid): RNA is a nucleic acid that plays a crucial role in the process of gene expression. It carries genetic information from DNA to the ribosomes, where proteins are synthesized. RNA is made up of a long chain of nucleotides, just like DNA, but with some key differences in its structure and composition.
2. Transfer: In the context of biochemistry, "transfer" refers to the movement or transport of molecules from one location to another within a cell or between cells. This process is often facilitated by specific proteins or other molecular carriers.
3. Lys (Lysine): Lysine is an essential amino acid that cannot be synthesized by the human body and must be obtained through diet. It plays important roles in various biological processes, including protein synthesis, enzyme function, hormone production, and energy metabolism. In molecular biology, lysine is often used as a marker for certain types of modifications to proteins or nucleic acids.

Therefore, "RNA, Transfer, Lys" could refer to the transfer RNA (tRNA) molecule that carries a specific amino acid, such as lysine, to the ribosome during protein synthesis. The tRNA molecule recognizes a specific codon on the messenger RNA (mRNA) and brings the corresponding amino acid to the growing polypeptide chain, allowing for the translation of genetic information into a functional protein.

An anticodon is a sequence of three ribonucleotides (RNA bases) in a transfer RNA (tRNA) molecule that pair with a complementary codon in a messenger RNA (mRNA) molecule during protein synthesis. This interaction occurs within the ribosome during translation, where the genetic code in the mRNA is translated into an amino acid sequence in a polypeptide. Specifically, each tRNA carries a specific amino acid that corresponds to its anticodon sequence, allowing for the accurate and systematic addition of amino acids to the growing polypeptide chain.

In summary, an anticodon is a crucial component of the translation machinery, facilitating the precise decoding of genetic information and enabling the synthesis of proteins according to the instructions encoded in mRNA molecules.

Thionucleosides are a type of modified nucleoside where the oxygen atom in the sugar component (ribose or deoxyribose) is replaced by a sulfur atom. This modification can occur naturally or be introduced synthetically. The resulting compounds have been studied for their potential biological activity, including antiviral and anticancer properties. However, they are not typically used as a standard medical treatment at this time.

Thiamine, also known as vitamin B1, is a water-soluble vitamin that plays a crucial role in certain metabolic reactions, particularly in the conversion of carbohydrates into energy in the body. It is essential for the proper functioning of the heart, nerves, and digestive system. Thiamine acts as a cofactor for enzymes involved in the synthesis of neurotransmitters and the metabolism of carbohydrates, lipids, and proteins. Deficiency in thiamine can lead to serious health complications, such as beriberi (a disease characterized by peripheral neuropathy, muscle wasting, and heart failure) and Wernicke-Korsakoff syndrome (a neurological disorder often seen in alcoholics due to chronic thiamine deficiency). Thiamine is found in various foods, including whole grains, legumes, pork, beef, and fortified foods.

Thiosulfate Sulfurtransferase (TST) is an enzyme that catalyzes the transfer of a sulfur group from thiosulfate to a range of acceptor molecules. It plays a crucial role in the detoxification of harmful substances and the maintenance of cellular redox balance. TST is also known as Rhodanese, which comes from the Greek word "rhodanos," meaning rose-red, due to the pinkish-red color of the enzyme when it was first isolated.

The systematic medical definition of Thiosulfate Sulfurtransferase is:

A mitochondrial matrix enzyme (EC 2.8.1.1) that catalyzes the transfer of a sulfur atom from thiosulfate to cyanide, forming thiocyanate and sulfite. This reaction serves as a detoxification pathway for cyanide in the body. TST also plays a role in maintaining cellular redox balance by participating in the reduction of oxidized proteins and other molecules.

Oligoribonucleotides are short, synthetic chains of ribonucleotides, which are the building blocks of RNA (ribonucleic acid). These chains typically contain fewer than 20 ribonucleotide units, and can be composed of all four types of nucleotides found in RNA: adenine (A), uracil (U), guanine (G), and cytosine (C). They are often used in research for various purposes, such as studying RNA function, regulating gene expression, or serving as potential therapeutic agents.

tRNA (transfer RNA) methyltransferases are a group of enzymes that catalyze the transfer of a methyl group (-CH3) to specific positions on the tRNA molecule. These enzymes play a crucial role in modifying and regulating tRNA function, stability, and interaction with other components of the translation machinery during protein synthesis.

The addition of methyl groups to tRNAs can occur at various sites, including the base moieties of nucleotides within the anticodon loop, the TψC loop, and the variable region. These modifications help maintain the structural integrity of tRNA molecules, enhance their ability to recognize specific codons during translation, and protect them from degradation by cellular nucleases.

tRNA methyltransferases are classified based on the type of methylation they catalyze:

1. N1-methyladenosine (m1A) methyltransferases: These enzymes add a methyl group to the N1 position of adenosine residues in tRNAs. An example is TRMT6/TRMT61A, which methylates adenosines at position 58 in human tRNAs.
2. N3-methylcytosine (m3C) methyltransferases: These enzymes add a methyl group to the N3 position of cytosine residues in tRNAs. An example is Dnmt2, which methylates cytosines at position 38 in various organisms.
3. N7-methylguanosine (m7G) methyltransferases: These enzymes add a methyl group to the N7 position of guanosine residues in tRNAs, primarily at position 46 within the TψC loop. An example is Trm8/Trm82, which catalyzes this modification in yeast and humans.
4. 2'-O-methylated nucleotides (Nm) methyltransferases: These enzymes add a methyl group to the 2'-hydroxyl group of ribose sugars in tRNAs, which can occur at various positions throughout the molecule. An example is FTSJ1, which methylates uridines at position 8 in human tRNAs.
5. Pseudouridine (Ψ) synthases: Although not technically methyltransferases, pseudouridine synthases catalyze the isomerization of uridine to pseudouridine, which can enhance tRNA stability and function. An example is Dyskerin (DKC1), which introduces Ψ at various positions in human tRNAs.

These enzymes play crucial roles in modifying tRNAs, ensuring proper folding, stability, and function during translation. Defects in these enzymes can lead to various diseases, including neurological disorders, cancer, and premature aging.

Thiouracil is not typically used as a medical treatment in current clinical practice. It is an anti-thyroid medication that was historically used to manage hyperthyroidism, particularly in cases of Graves' disease. However, due to its adverse effect profile and the availability of safer and more effective treatment options, thiouracil has largely been replaced by other medications such as methimazole and propylthiouracil.

Thiouracil works by inhibiting the enzyme thyroperoxidase, which is necessary for the production of thyroid hormones in the body. By blocking this enzyme, thiouracil reduces the amount of thyroid hormones produced and can help to control symptoms of hyperthyroidism such as rapid heart rate, tremors, and weight loss.

While thiouracil is still available for use in some cases, its use is generally reserved for patients who cannot tolerate or have failed other treatments. The medication can cause serious side effects, including liver damage, bone marrow suppression, and allergic reactions, and requires careful monitoring during treatment.

Cytidine is a nucleoside, which consists of the sugar ribose and the nitrogenous base cytosine. It is an important component of RNA (ribonucleic acid), where it pairs with guanosine via hydrogen bonding to form a base pair. Cytidine can also be found in some DNA (deoxyribonucleic acid) sequences, particularly in viral DNA and in mitochondrial DNA.

Cytidine can be phosphorylated to form cytidine monophosphate (CMP), which is a nucleotide that plays a role in various biochemical reactions in the body. CMP can be further phosphorylated to form cytidine diphosphate (CDP) and cytidine triphosphate (CTP), which are involved in the synthesis of lipids, glycogen, and other molecules.

Cytidine is also available as a dietary supplement and has been studied for its potential benefits in treating various health conditions, such as liver disease and cancer. However, more research is needed to confirm these potential benefits and establish safe and effective dosages.

Bacterial RNA refers to the genetic material present in bacteria that is composed of ribonucleic acid (RNA). Unlike higher organisms, bacteria contain a single circular chromosome made up of DNA, along with smaller circular pieces of DNA called plasmids. These bacterial genetic materials contain the information necessary for the growth and reproduction of the organism.

Bacterial RNA can be divided into three main categories: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information copied from DNA, which is then translated into proteins by the rRNA and tRNA molecules. rRNA is a structural component of the ribosome, where protein synthesis occurs, while tRNA acts as an adapter that brings amino acids to the ribosome during protein synthesis.

Bacterial RNA plays a crucial role in various cellular processes, including gene expression, protein synthesis, and regulation of metabolic pathways. Understanding the structure and function of bacterial RNA is essential for developing new antibiotics and other therapeutic strategies to combat bacterial infections.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Sulfur is not typically referred to in the context of a medical definition, as it is an element found in nature and not a specific medical condition or concept. However, sulfur does have some relevance to certain medical topics:

* Sulfur is an essential element that is a component of several amino acids (the building blocks of proteins) and is necessary for the proper functioning of enzymes and other biological processes in the body.
* Sulfur-containing compounds, such as glutathione, play important roles in antioxidant defense and detoxification in the body.
* Some medications and supplements contain sulfur or sulfur-containing compounds, such as dimethyl sulfoxide (DMSO), which is used topically for pain relief and inflammation.
* Sulfur baths and other forms of sulfur-based therapies have been used historically in alternative medicine to treat various conditions, although their effectiveness is not well-established by scientific research.

It's important to note that while sulfur itself is not a medical term, it can be relevant to certain medical topics and should be discussed with a healthcare professional if you have any questions or concerns about its use in medications, supplements, or therapies.

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.

In the context of medicine and toxicology, sulfides refer to inorganic or organic compounds containing the sulfide ion (S2-). Sulfides can be found in various forms such as hydrogen sulfide (H2S), metal sulfides, and organic sulfides (also known as thioethers).

Hydrogen sulfide is a toxic gas with a characteristic rotten egg smell. It can cause various adverse health effects, including respiratory irritation, headaches, nausea, and, at high concentrations, loss of consciousness or even death. Metal sulfides, such as those found in some minerals, can also be toxic and may release hazardous sulfur dioxide (SO2) when heated or reacted with acidic substances.

Organic sulfides, on the other hand, are a class of organic compounds containing a sulfur atom bonded to two carbon atoms. They can occur naturally in some plants and animals or be synthesized in laboratories. Some organic sulfides have medicinal uses, while others may pose health risks depending on their concentration and route of exposure.

It is important to note that the term "sulfide" has different meanings in various scientific contexts, so it is essential to consider the specific context when interpreting this term.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

4-Thiouridine is an atypical nucleotide formed with the 4-thiouracil base found in transfer RNA (tRNA). Its biosynthesis has ...
4-Thiouridine, MP Biomedicals—An anti-metabolite and a photoactivable uridine analogue used as an affinity label and to ... 4-thiouridine, thiouridine, uridine, 4-thio, 1-beta-d-ribofuranosyl-4-thiouracil, 1-2r,3r,4s,5r-3,4-dihydroxy-5-hydroxymethyl ... 4-thiouridine, thiouridine, uridine, 4-thio, 1-beta-d-ribofuranosyl-4-thiouracil, 1-2r,3r,4s,5r-3,4-dihydroxy-5-hydroxymethyl ... 4-Thiouridine, MP Biomedicals is an anti-metabolite and a photoactivable uridine analogue used as an affinity label. It is a ...
2-Thiouridine shows activity against DENV and SARS-CoV-2 ssRNA+ viruses. Oct. 30, 2023 ... Researchers from Hokkaido University (Japan) and colleagues have identified 2-thiouridine (s2U) as a broad-spectrum antiviral ...
THUMP; The THUMP domain is named after after thiouridine synthases, methylases and PSUSs. cl17173. Location:274 → 353. AdoMet_ ... THUMP; The THUMP domain is named after after thiouridine synthases, methylases and PSUSs. cl17173. Location:181 → 326. AdoMet_ ... THUMP; The THUMP domain is named after after thiouridine synthases, methylases and PSUSs. cl17173. Location:165 → 310. AdoMet_ ... THUMP; The THUMP domain is named after after thiouridine synthases, methylases and PSUSs. cl17173. Location:274 → 323. AdoMet_ ...
Optional 4-thiouridine pre-incubation and UV-A crosslinking could be used for certain proteins. 4-thiouridine enhances ... Optional - Thiouridine labeling and UV-A crosslinking (alternative to step 1.2). • Add 50 μL of 4SU (stock concentration: 100 ... Alternatively, add 10 μL of 4-thiouridine (stock concentration: 100 mM) to get a final concentration of 100 μM 4SU. ... Incubate cells with 4-thiouridine for 60 min at 500 μM or 8 h at 100 mM. Check cell viability. ...
tRNA 2-thiouridine(34) synthase MnmA 8690 3-oxoacyl-[acyl-carrier-protein] reductase ...
Agonists: 2-Thiouridine 5-triphosphate. *Neuropeptide Y. *Neuropeptide Y (13-36). *Peptide YY ...
5-aminomethyl-2-thiouridine 5-monophosphate residue 5-carboxymethylaminomethyl-2-O-methyluridine 5-monophosphate residue ...
Sylvers, L. A., Rogers, K. C., Shimizu, M., Ohtsuka, E. & Soll, D. A 2-thiouridine derivative in tRNAGlu is a positive ... Mtu1-mediated thiouridine formation of mitochondrial tRNAs is required for mitochondrial translation and is involved in ...
Xu, J.; Green, N.J.; Gibard, C.; Krishnamurthy, R.; Sutherland, J.D. Prebiotic phosphorylation of 2-thiouridine provides either ...
3 4-Thiouridine Labeling to Analyze mRNA Turnover in Schizosaccharomyces pombe. Juan Mata and Jo Ann Wise. CHAPTER 6 ...
3 4-Thiouridine Labeling to Analyze mRNA Turnover in Schizosaccharomyces pombe. Juan Mata and Jo Ann Wise. CHAPTER 6 ...
3 4-Thiouridine Labeling to Analyze mRNA Turnover in Schizosaccharomyces pombe. Juan Mata and Jo Ann Wise. CHAPTER 6 ...
In 4-thiouridine biosynthesis, ThiI adenylates the tRNA uridine and transfers sulfur from a persulfide formed on the protein. ... ThiI is a bifunctional enzyme required for the synthesis of both the 4-thiouridine modification in tRNA and the thiazole moiety ... In 4-thiouridine biosynthesis, ThiI adenylates the tRNA uridine and transfers sulfur from a persulfide formed on the protein. ... In Salmonella enterica, ThiI is a bifunctional enzyme required for the synthesis of both the 4-thiouridine modification in tRNA ...
A selective and sensitive detection system for 4-thiouridine modification in RNA. RNA. 2022 Nov 21:rna.079445.122. doi: 10.1261 ... Biochemical and structural characterization of oxygen-sensitive 2-thiouridine synthesis catalyzed by an iron-sulfur protein ...
... after incubation with 4-thio-uridine7. We also adapted the mRNA interactome capture protocol to yeast (see Methods and ... for yeast and 4-thiouridine (4SU) for HuH-7 cells, respectively. Conventional crosslinking (cCL) in yeast did not yield ...
Journal Article] Mtu1-mediated thiouridine formation of mitochondrial tRNAs is required for mitochondrial translation and is ... Journal Article] Biochemical and structural characterization of oxygen-sensitive 2-thiouridine synthesis catalyzed by an iron- ...
6-Thiopurine, 6-thiopurine riboside, 6-thioguanine, 6-thioguanosine, 8-thioguanosine, 2-thiouracil, 4-thiouridine, 2- ...
Triplets with 2-thiouridine residues were transcribed as for their corresponding U, replacing UTP with U2STP (Jena Bioscience ( ...
Metabolic tagging of newly transcribed RNA by 4-thiouridine (4sU) can reveal the relative contributions of RNA synthesis and ...
tRNA-with-5-taurinomethyl-2-thiouridine. *tRNA_containing_5-taurinomethyl-2-thiouridine ...
5-aminomethyl-2-thiouridine-5-monophosphate. Short name. pnm5s2U. MODOMICS code new. 2002510551U. ...
... changes in the tRNA wobble base modification 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U) lead to codon-biased gene- ...
CC -!- The enzyme from the bacterium Escherichia coli forms 4-thiouridine CC only at position 8 of tRNA. CC -!- The enzyme also ... a 4-thiouridine in tRNA + AMP + diphosphate + CA 2 oxidized [2Fe-2S]-[ferredoxin]. CC -!- The enzyme, found in bacteria and ...
scientific article published on January 1, 1976
2-thiouridine. s2U. 46. dihydrouridine. D. 47. 4-thiouridine. s4U. 48. 5-formylcytidine. f5c. ...
2-thiouridine is a broad-spectrum antiviral nucleoside analogue against positive-strand RNA viruses. Uemura, K., Nobori, H., ...
A knowledge graph of biological entities such as genes, gene functions, diseases, phenotypes and chemicals. Embeddings are generated with Walking RDF and OWL method ...
Agonists: 2-Thiouridine 5-triphosphate. *Neuropeptide Y. *Neuropeptide Y (13-36). *Peptide YY ...
Agonists: 2-Thiouridine 5-triphosphate. *Neuropeptide Y. *Neuropeptide Y (13-36). *Peptide YY ...

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