Purification, characterization and crystallization of thermostable anthranilate phosphoribosyltransferase from Sulfolobus solfataricus. (1/37)Anthranilate phosphoribosyltransferase (TrpD; EC 188.8.131.52) from the hyperthermophilic archaeon Sulfolobus solfataricus (ssTrpD) was expressed in Escherichia coli, purified and crystallized. Analytical gel permeation chromatography revealed a homodimeric composition of the enzyme. The steady-state kinetic characteristics suggest tight binding of the substrate anthranilic acid and efficient catalysis at the physiological growth temperature of S. solfataricus. Crystals of ssTrpD diffract to better than 2.6 A resolution and preliminary X-ray characterization was carried out. The crystals are suitable for structure determination. (+info)
Replacement of the yeast TRP4 3' untranslated region by a hammerhead ribozyme results in a stable and efficiently exported mRNA that lacks a poly(A) tail. (2/37)The mRNA poly(A) tail serves different purposes, including the facilitation of nuclear export, mRNA stabilization, efficient translation, and, finally, specific degradation. The posttranscriptional addition of a poly(A) tail depends on sequence motifs in the 3' untranslated region (3' UTR) of the mRNA and a complex trans-acting protein machinery. In this study, we have replaced the 3' UTR of the yeast TRP4 gene with sequences encoding a hammerhead ribozyme that efficiently cleaves itself in vivo. Expression of the TRP4-ribozyme allele resulted in the accumulation of a nonpolyadenylated mRNA. Cells expressing the TRP4-ribozyme mRNA showed a reduced growth rate due to a reduction in Trp4p enzyme activity. The reduction in enzyme activity was not caused by inefficient mRNA export from the nucleus or mRNA destabilization. Rather, analyses of mRNA association with polyribosomes indicate that translation of the ribozyme-containing mRNA is impaired. This translational defect allows sufficient synthesis of Trp4p to support growth of trp4 cells, but is, nevertheless, of such magnitude as to activate the general control network of amino acid biosynthesis. (+info)
Structural analysis of two enzymes catalysing reverse metabolic reactions implies common ancestry. (3/37)The crystal structure of the dimeric anthranilate phosphoribosyltransferase (AnPRT) reveals a new category of phosphoribosyltransferases, designated as class III. The active site of this enzyme is located within the flexible hinge region of its two-domain structure. The pyrophosphate moiety of phosphoribosylpyrophosphate is co-ordinated by a metal ion and is bound by two conserved loop regions within this hinge region. With the structure of AnPRT available, structural analysis of all enzymatic activities of the tryptophan biosynthesis pathway is complete, thereby connecting the evolution of its enzyme members to the general development of metabolic processes. Its structure reveals it to have the same fold, topology, active site location and type of association as class II nucleoside phosphorylases. At the level of sequences, this relationship is mirrored by 13 structurally invariant residues common to both enzyme families. Taken together, these data imply common ancestry of enzymes catalysing reverse biological processes--the ribosylation and deribosylation of metabolic pathway intermediates. These relationships establish new links for enzymes involved in nucleotide and amino acid metabolism. (+info)
The crystal structure of anthranilate phosphoribosyltransferase from the enterobacterium Pectobacterium carotovorum. (4/37)The structure of anthranilate phosphoribosyltransferase from the enterobacterium Pectobacterium carotovorum has been solved at 2.4 A in complex with Mn(2+)-pyrophosphate, and at 1.9 A without ligands. The enzyme structure has a novel phosphoribosyltransferase (PRT) fold and displays close homology to the structures of pyrimidine nucleoside phosphorylases. The enzyme is a homodimer with a monomer of 345 residues. Each monomer consists of two subdomains, alpha and alpha/beta, which form a cleft containing the active site. The nature of the active site is inferred from the trapped MnPPi complex and detailed knowledge of the active sites of nucleoside phosphorylases. With the anthranilate (An)PRT structure solved, the structures of all the enzymes required for tryptophan biosynthesis are now known. (+info)
Anthranilate synthase can generate sufficient phosphoribosyl amine for thiamine synthesis in Salmonella enterica. (5/37)In bacteria, the biosynthetic pathway for the hydroxymethyl pyrimidine moiety of thiamine shares metabolic intermediates with purine biosynthesis. The two pathways branch after the compound aminoimidazole ribotide. Past work has shown that the first common metabolite, phosphoribosyl amine (PRA), can be generated in the absence of the first enzyme in purine biosynthesis, PurF. PurF-independent PRA synthesis is dependent on both strain background and growth conditions. Standard genetic approaches have not identified a gene product singly responsible for PurF-independent PRA formation. This result has led to the hypothesis that multiple enzymes contribute to PRA synthesis, possibly as the result of side products from their dedicated reaction. A mutation that was able to restore PRA synthesis in a purF gnd mutant strain was identified and found to map in the gene coding for the TrpD subunit of the anthranilate synthase (AS)-phosphoribosyl transferase (PRT) complex. Genetic analyses indicated that wild-type AS-PRT was able to generate PRA in vivo and that the P362L mutant of TrpD facilitated this synthesis. In vitro activity assays showed that the mutant AS was able to generate PRA from ammonia and phosphoribosyl pyrophosphate. This work identifies a new reaction catalyzed by AS-PRT and considers it in the context of cellular thiamine synthesis and metabolic flexibility. (+info)
The importance of surface loops for stabilizing an eightfold beta alpha barrel protein. (6/37)An important step in understanding how a protein folds is to determine those regions of the sequence that are critical to both its stability and its folding pathway. We chose phosphoribosyl anthranilate isomerase from Escherichia coli, which is a monomeric representative of the (beta alpha)8 barrel family of proteins, to construct a variant that carries an internal tandem duplication of the fifth beta alpha module. This (beta alpha)9 variant was enzymically active and therefore must have a wild-type (beta alpha)8 core. It had a choice a priori to fold to three different folding frames, which are distinguished by carrying the duplicated segment as an insert into one out of three different loops. Steady-state kinetic constants, the fluorescence properties of a crucial tryptophan residue, and limited proteolysis showed that the stable (beta alpha)9 variant carries the insertion between beta-strand 5 and alpha-helix 5. This preference can be explained by the important role of loops between alpha helices and beta strands in stabilizing the structure of the enzyme. (+info)
Sequence-specific initiator elements focus initiation of transcription to distinct sites in the yeast TRP4 promoter. (7/37)Transcription from the yeast TRP4 promoter initiates at two basal (i127 and i76) and three GCN4 dependent (i31, i25 and i12) initiator elements. All of these elements contain not more than one deviation from the earlier proposed initiator consensus sequence PuPuPyPuPu, a pyrimidine nucleotide flanked on either side by two purine nucleotides. A point mutation analysis of these elements in various combinations was performed and revealed that the central pyrimidine nucleotide and at least one of the 3' flanking purine nucleotides of the PuPuPyPuPu consensus sequence are essential but alone not sufficient to define a functional initiator element. Multiple cryptic transcription start sites, which function independently whether they are located on the coding or the non-coding strand, can replace the function of mutated initiator elements and therefore the overall level of transcription initiation is not affected. The sequence specificity is identical for basal and GCN4 dependent initiator elements demonstrating that they are functionally homologous. These findings imply that the role of initiator elements is to 'focus' the start point(s) of transcription to distinct sites located in the region between the site(s) of the assembly of the transcriptional complex and the start codon of translation. (+info)
Genes for tryptophan biosynthesis in the halophilic archaebacterium Haloferax volcanii: the trpDFEG cluster. (8/37)Tryptophan auxotrophs of the archaebacterium Haloferax volcanii define a cluster of overlapping genes homologous to eubacterial-eukaryotic trpD, -F, -E, and -G, linked in that order and each preceded by a possible ribosome binding site. Residues involved in feedback inhibition of eubacterial anthranilate synthetases are conserved. (+info)
Anthranilate Phosphoribosyltransferase (APRT) is an enzyme that plays a crucial role in the biosynthesis of purines, which are essential building blocks of nucleic acids such as DNA and RNA. APRT catalyzes the transfer of a phosphoribosyl group from 5-phosphoribosyl-1-pyrophosphate (PRPP) to anthranilate, a derivative of tryptophan, to form 6-phosphoribosylanthranilate (6-PRA). This reaction is the first step in the synthesis of the purine base adenine. Mutations in the APRT gene can lead to a deficiency in APRT activity, resulting in a rare genetic disorder called Lesch-Nyhan syndrome (LNS). LNS is characterized by high levels of uric acid in the blood and urine, as well as neurological symptoms such as self-mutilation and intellectual disability. APRT deficiency can also cause other related conditions, such as Lesch-Nyhan-like syndrome and non-Lesch-Nyhan purine overproduction syndrome. In the medical field, APRT is an important enzyme to study and understand for the diagnosis and treatment of LNS and related conditions. Enzyme replacement therapy and other treatments have been developed to manage the symptoms of LNS and improve the quality of life for affected individuals.
Pyrimidine Phosphorylases are enzymes that play a crucial role in the metabolism of pyrimidine nucleotides in the body. Pyrimidines are a class of nitrogen-containing heterocyclic compounds that are essential building blocks of nucleic acids, such as DNA and RNA. Pyrimidine Phosphorylases are responsible for the breakdown of pyrimidine nucleotides into their constituent parts, which can then be reused by the body for the synthesis of new nucleotides. There are two main types of Pyrimidine Phosphorylases: Purine Phosphorylase (PP) and Thymidine Phosphorylase (TP). PP is primarily found in the liver and kidneys, where it is involved in the breakdown of purines, which are another class of nitrogen-containing heterocyclic compounds. TP, on the other hand, is primarily found in the liver, spleen, and bone marrow, where it is involved in the breakdown of thymidine, a nucleotide that is a component of DNA. Deficiencies in Pyrimidine Phosphorylases can lead to a variety of health problems, including bone marrow failure, neurological disorders, and immunodeficiency. In some cases, these deficiencies can be treated with enzyme replacement therapy, which involves the administration of the missing enzyme to the body.
Anthranilate synthase is an enzyme that plays a key role in the biosynthesis of the amino acid tryptophan in plants, fungi, and some bacteria. It catalyzes the conversion of chorismate, a precursor molecule, into anthranilate, which is a key intermediate in the tryptophan biosynthesis pathway. In the medical field, anthranilate synthase has been studied as a potential target for the development of new antibiotics and herbicides. For example, some bacteria that are resistant to conventional antibiotics have been found to produce anthranilate synthase enzymes that are different from those found in susceptible bacteria. This has led to the development of new antibiotics that target these enzymes. In addition, anthranilate synthase has been studied as a potential target for the development of herbicides that selectively kill certain plant species. This is because the enzyme is not present in all plant species, and its inhibition can lead to the death of specific plants without harming other crops or non-target organisms. Overall, anthranilate synthase is an important enzyme in the biosynthesis of tryptophan and has potential applications in the development of new antibiotics and herbicides.
Hypoxanthine phosphoribosyltransferase (HPRT) is an enzyme that plays a crucial role in the metabolism of purines, which are important components of DNA and RNA. Specifically, HPRT catalyzes the conversion of hypoxanthine to inosine monophosphate (IMP) and xanthine to xanthosine monophosphate (XMP). These reactions are the first steps in the salvage pathway for purine biosynthesis, which allows cells to recycle and reuse purine bases that are present in the environment. In the medical field, HPRT deficiency is a rare genetic disorder that results from a deficiency in the HPRT enzyme. This deficiency can lead to the accumulation of toxic levels of hypoxanthine and xanthine in the body, which can cause a range of symptoms including liver damage, kidney damage, and neurological problems. HPRT deficiency is typically diagnosed through genetic testing and can be treated with a combination of dietary restrictions and medications that help to lower the levels of toxic purines in the body.
Adenine Phosphoribosyltransferase (APRT) is an enzyme that plays a crucial role in the metabolism of purines, which are essential building blocks of DNA and RNA. APRT catalyzes the transfer of a ribose moiety from 5-phosphoribosyl-1-pyrophosphate (PRPP) to adenine, forming AMP (adenosine monophosphate) and PPi (pyrophosphate). In the medical field, APRT deficiency is a rare genetic disorder that results from a deficiency in the APRT enzyme. This deficiency leads to an accumulation of uric acid and its derivatives in the body, which can cause a range of health problems, including kidney stones, gout, and kidney failure. APRT deficiency is typically inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the defective gene (one from each parent) to develop the disorder. Diagnosis of APRT deficiency typically involves blood tests to measure uric acid levels and genetic testing to identify mutations in the APRT gene. Treatment for APRT deficiency typically involves lifelong management of uric acid levels through dietary modifications, medications, and, in severe cases, kidney transplantation.
Pentosyltransferases are a group of enzymes that transfer a pentose sugar moiety from one molecule to another. In the medical field, pentosyltransferases are important in the metabolism of carbohydrates, nucleic acids, and other biomolecules. They play a role in the synthesis of various compounds, including nucleotides, glycosaminoglycans, and other complex carbohydrates. Pentosyltransferases are also involved in the breakdown of certain molecules, such as heparan sulfate and dermatan sulfate. Mutations in genes encoding pentosyltransferases can lead to various diseases, including mucopolysaccharidoses and other lysosomal storage disorders.
Ortho-aminobenzoates are a class of organic compounds that contain an amino group (-NH2) attached to a benzene ring with the nitrogen atom in an ortho position, meaning it is located at one of the two carbon atoms adjacent to the ring. In the medical field, ortho-aminobenzoates are commonly used as antiseptics and disinfectants. They are effective against a wide range of microorganisms, including bacteria, viruses, and fungi. Some examples of ortho-aminobenzoates used in medicine include chlorhexidine, which is used as an antiseptic in mouthwashes and throat lozenges, and benzalkonium chloride, which is used as a disinfectant in various medical and surgical applications. In addition to their antiseptic and disinfectant properties, ortho-aminobenzoates have also been studied for their potential therapeutic applications. For example, some ortho-aminobenzoates have been shown to have anti-inflammatory and analgesic effects, and they are being investigated as potential treatments for conditions such as rheumatoid arthritis and osteoarthritis.
Orotate phosphoribosyltransferase (OPRTase) is an enzyme that plays a crucial role in the biosynthesis of the nucleotide uridine monophosphate (UMP) in the human body. UMP is a key intermediate in the synthesis of all nucleotides, including DNA and RNA. OPRTase catalyzes the transfer of a phosphoribosyl group from phosphoribosylpyrophosphate (PRPP) to orotic acid, forming orotidine monophosphate (OMP). This reaction is the first step in the de novo synthesis of UMP, which is necessary for the production of all other nucleotides. Mutations in the gene encoding OPRTase can lead to a deficiency in the enzyme, resulting in a rare genetic disorder called orotic aciduria. This disorder is characterized by the accumulation of orotic acid and its toxic metabolites in the body, leading to neurological and developmental problems in affected individuals.
Nicotinamide Phosphoribosyltransferase (NAMPT) is an enzyme that plays a critical role in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), a coenzyme involved in various cellular processes, including energy metabolism, DNA repair, and inflammation. NAMPT is also known as the rate-limiting enzyme in the NAD+ salvage pathway, which recycles NAD+ from its degradation products. In the medical field, NAMPT has gained attention as a potential therapeutic target for various diseases, including cancer, neurodegenerative disorders, and metabolic disorders. NAMPT is often upregulated in cancer cells, leading to increased NAD+ biosynthesis and enhanced cell survival and proliferation. Inhibiting NAMPT activity has been shown to reduce cancer cell growth and sensitize cancer cells to chemotherapy. In addition, NAMPT has been implicated in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease, as well as metabolic disorders such as type 2 diabetes and obesity. In these conditions, NAMPT activity is often dysregulated, leading to reduced NAD+ levels and impaired cellular function. Therefore, targeting NAMPT has emerged as a promising therapeutic strategy for the treatment of various diseases. Several NAMPT inhibitors have been developed and are currently being tested in preclinical and clinical studies.
Lesch-Nyhan syndrome is a rare genetic disorder that affects primarily males. It is caused by a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT), which is involved in the metabolism of purines, a type of nitrogen-containing base found in DNA and RNA. The symptoms of Lesch-Nyhan syndrome typically begin in early childhood and include self-injurious behavior, such as biting, hitting, and head-banging, as well as intellectual disability, spasticity, and problems with speech and language. Affected individuals also have an increased risk of developing gout, a type of arthritis caused by the buildup of uric acid crystals in the joints. Lesch-Nyhan syndrome is inherited in an X-linked recessive pattern, which means that it is caused by a mutation in the HPRT gene located on the X chromosome. Since males have only one X chromosome, they are more likely to be affected by the disorder than females, who have two X chromosomes and can inherit a normal copy from one parent to compensate for the mutated copy.
Table 2 - Comparative Omics Analysis of Historic and Recent Isolates of Bordetella pertussis and Effects of Genome...
Current and future treatments for tuberculosis - PubMed
Table 2 - Comparative Omics Analysis of Historic and Recent Isolates of Bordetella pertussis and Effects of Genome...
Code System Concept
NDF-RT Code NDF-RT Name
Regulon of Trp leader in Klebsiella pneumoniae subsp. pneumoniae MGH 78578
Division of AIDS Anti-HIV/OI/TB Therapeutics Database - Surveillance Memo
Family Search for PF06004 (DUF903)
Pentosephosphates | DrugBank Online
Pesquisa | Prevenção e Controle de Câncer
- It exists in a complex with ANTHRANILATE SYNTHASE in bacteria. (bvsalud.org)
- En las bacterias existe en complejo con la ANTRANILATO SINTASA EC 184.108.40.206. (bvsalud.org)