Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The FHLA protein is the transcriptional regulator of the genes of the formate regulon from Escherichia coli. The protein shares homology with the sigma 54-dependent regulators of the NTRC family in the central and C-terminal domains but differs in possessing an extended N terminus lacking the aspartate residue which is the site of phosphorylation. Purified FHLA displays intrinsic ATPase activity which is stimulated weakly by formate and DNA. The presence of both formate and DNA carrying the upstream regulatory sequence to which FHLA binds leads to a large increase in the rate of ATP hydrolysis. Hypophosphite, a structural analog of formate, and azide, a transition state analog of formate, also stimulate ATPase activity, supporting the conclusion that formate is a direct ligand of FHLA. Half-maximal saturation of FHLA with formate took place at around 5 mM, and half-maximal saturation with target DNA took place at around 50 nM. The stimulation of ATPase activity by formate was conferred by a decrease in the apparent Km for ATP, whereas the effect of the DNA binding site also affected the Kcat of the reaction. The other nucleoside triphosphates, GTP, UTP, and CTP, competed with ATP cleavage by FHLA, suggesting at least their binding to FHLA. The specific ATPase activity of FHLA was dependent on the concentration of FHLA in the assay, especially in the presence of DNA and formate. Direct liganding of the effector, therefore, leads to the same consequence as phosphorylation for the NTRC-type regulators, namely, stimulation of ATPase activity.
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PMID:Effector-mediated stimulation of ATPase activity by the sigma 54-dependent transcriptional activator FHLA from Escherichia coli. 775 Dec 89

The TyrR protein of Escherichia coli is the chief transcriptional regulator of several genes essential for aromatic amino acid biosynthesis and transport. It was established in previous studies that this protein binds ATP, that the TyrR.ATP complex has enhanced affinity for tyrosine, and that the susceptibility of the TyrR protein to hydrolysis by trypsin is altered by ATP. Here we show that the TyrR protein has ATPase activity, which is stimulated by tyrosine. In this respect the TyrR protein resembles the transcriptional activator NtrC. The NtrC protein contains an internal polypeptide segment, 220 amino acid residues in length, with a high degree of identity to the TyrR protein, that contains the presumptive ATPase catalytic center.
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PMID:ATPase activity of TyrR, a transcriptional regulatory protein for sigma 70 RNA polymerase. 851 43

The highly differentiated gastric parietal cell has a characteristic morphology and plays a specialized role in the hydrochloric acid secretion into the stomach lumen. The major enzyme in this system is an ATP-driven proton pump, the H+/K(+)-ATPase, which is responsible for proton translocation across the apical plasma membrane. The primary structures of the catalytic alpha and glycosylated beta subunits, and their transmembrane topology are similar to those of the corresponding subunits of Na+/K(+)-ATPase, suggesting that the reaction mechanism of both ATPases would be essentially the same if not identical. Most of the positions of introns in the H+/K(+)-ATPase subunit gene. These findings suggest that the alpha and beta subunit genes, respectively, of the two ATPases were derived from the common ancestors. We found that a DNA sequence motif, (G/C)PuPu(G/C)NGAT(A/T)PuPy, was located in the upstream regions of both alpha and beta subunit genes from human and rat. This motif may be a binding site for a positive transcriptional regulator that functions specifically in the parietal cells. cDNA cloning and in situ hybridization demonstrated that novel zinc finger proteins (GATA-GT1 and GATA-GT2) are present in the gastric parietal cells. These proteins bind to the (G/C)PuPu(G/C)NGAT(A/T)PuPy motif. Furthermore, they activate the transcription of the reporter gene with the 5'-upstream region of the alpha or beta subunit gene. These results suggest that gastric GATA DNA-binding proteins play important roles in transcriptional activation of H+/K(+)-ATPase genes in the parietal cells.
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PMID:[Genes for gastric proton pump and their transcriptional regulation]. 871 77

The gastric H+/K(+)-ATPase is a P-type ATPase that is specifically expressed in gastric parietal cells and is responsible for acid secretion into the stomach. We have found one or more gastric mucosal nuclear proteins that recognize a sequence motif in the 5'-upstream regions of the H+/K(+)-ATPase alpha- and beta-subunit genes. This gastric motif, (G/C)PuPu(G/C)NGAT(A/T)PuPy, may be a binding site for a positive transcriptional regulator that functions specifically in parietal cells. We further demonstrated using cDNA cloning and in situ hybridization that novel zinc-finger proteins (GATA-GT1 and GATA-GT2) are present in the gastric parietal cells and bind to this motif. The proteins activate the transcription of the reporter gene with the 5'-upstream region of the H+/K(+)-ATPase beta-subunit gene. These results suggest that gastric GATA DNA-binding proteins have important roles in transcriptional activation of H+/K(+)-ATPase genes in the parietal cells.
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PMID:Roles of gastric GATA DNA-binding proteins. 886 76

Mutations at the yeast PDR1 transcriptional regulator locus are responsible for overexpression of the three ABC transporter genes PDR5, SNQ2 and YOR1, associated with the appearance of multiple drug resistance. The nucleotide sequences of 13 alleles of PDR1, comprising 6 multidrug resistance mutants, 1 intragenic suppressor and 6 wild types, have been determined. Single amino acid substitutions were shown to result from the mutations pdr1-2 (M308I), pdr1-3 (F815S), pdr1-6 (K302Q), pdr1-7 (P298A) and pdr1-8 (L1036 W), whereas the intragenic suppressor mutant pdr1-100 is deleted for the two amino acids L537 and A538. An isogenic series of strains was constructed containing the mutant alleles pdr1-3, pdr1-6 and pdr1-8 integrated into the genome. We found that the levels of resistance to cycloheximide, oligomycin, 4-nitroquinoline-N-oxide and ketoconazole were increased in all three mutants. The increase was more pronounced in the pdr1-3 than in the pdr1-6 and pdr1-8 mutants. Studies of the activity of the promoters of the ABC genes PDR5, SNQ2 and YOR1 demonstrated that the combination of the PDR5 promoter and the pdr1-3 mutation resulted in the highest level of promoter induction. Concomitantly, the level of PDR5 mRNA, of Pdr5p protein, and of its associated nucleoside triphosphatase activity, was strongly increased in the plasma membranes of the PDR1 mutants. Again, the pdr1-3 allele was associated with a stronger effect than the pdr1-8 and pdr1-6 alleles. The locations of the mutations in the PDR1 gene indicate that at least three different regions distributed throughout the Pdr1p transcription factor may be mutated to generate a Pdr1p with considerably increased transcriptional activation potency. These gain-of-function mutations support the concept, recently proposed, that in members of the large family of yeast Zn2Cys6 transcription factors a central inhibitory domain exists (delineated by the pdr1-7, pdr1-6 and pdr1-2 mutations). This domain may interact in a locked conformation with a putative, more C-terminally located inhibitory domain (mutated in pdr1-3), and with the putative activation domain (mutated in pdr1-8).
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PMID:Molecular and phenotypic characterization of yeast PDR1 mutants that show hyperactive transcription of various ABC multidrug transporter genes. 939 38

The cad operon of Staphylococcus aureus plasmid pI258, which confers cadmium resistance, encodes a transcriptional regulator, CadC, and CadA, an ATP-coupled Cd(II) pump that is a member of the superfamily of cation-translocating P-type ATPases. The Escherichia coli homologue of CadA, termed ZntA, is a Zn(II)/Cd(II) pump. The results described in this paper support the hypothesis that ZntA and CadA are Pb(II) pumps. First, CadC is a metal-responsive repressor that responds to soft metals in the order Pb>Cd>Zn. Second, both CadA and ZntA confer resistance to Pb(II). Third, transport of 65Zn(II) in everted membrane vesicles of E. coli catalyzed by either of these two P-type ATPase superfamily members is inhibited by Pb(II).
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PMID:Pb(II)-translocating P-type ATPases. 983

The TyrR protein of Escherichia coli (513 amino acid residues) is the chief transcriptional regulator of a group of genes that are essential for aromatic amino acid biosynthesis and transport. The TyrR protein can function either as a repressor or as an activator. The central region of the TyrR protein (residues 207 to 425) is similar to corresponding polypeptide segments of the NtrC protein superfamily. Like the NtrC protein, TyrR has intrinsic ATPase activity. Here, we report that TyrR possesses phosphatase activity. This activity is subject to inhibition by L-tyrosine and its analogues and by ATP and ATP analogues. Zinc ion (2 mM) stimulated the phosphatase activity of the TyrR protein by a factor of 57. The phosphatase-active site of TyrR was localized to a 31-kDa domain (residues 191 to 467) of the protein. However, mutational alteration of distant amino acid residues at both the N terminus and the C terminus of TyrR altered the phosphatase activity. Haemophilus influenzae TyrR (318 amino acid residues), a protein with a high degree of sequence similarity to the C terminus of the E. coli TyrR protein, exhibited a phosphatase activity similar to that of E. coli TyrR.
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PMID:The sigma(70) transcription factor TyrR has zinc-stimulated phosphatase activity that is inhibited by ATP and tyrosine. 1064 32

A 29 kb region of the circular chromosome of Agrobacterium tumefaciens containing genes required for bacterial attachment to host cells and virulence has been sequenced. Transposon mutants in many of the genes have been obtained. The mutants can be divided into two groups: those which can be complemented by conditioned medium and those whose phenotype is unaffected by conditioned medium. The first group includes mutants in genes with homology to ABC transporters, one possible transcriptional regulator, and some closely linked genes immediately downstream. The second group includes mutants in two possible transcriptional regulators, one ATPase, and a number of biosynthetic genes including a transacetylase required for the formation of an acetylated capsular polysaccharide. There are also several genes with no homology to genes of identified function. The presence of such a large number of genes required for attachment to host cells suggests that the ability of A. tumefaciens to bind to plant cells may play an important role in the life of these bacteria.
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PMID:A region of the Agrobacterium tumefaciens chromosome containing genes required for virulence and attachment to host cells. 1078 39

ZntA is a cation-translocating ATPase which exports from Escherichia coli Cd(II) and Pb(II), as well as Zn(II). The metal-dependent ATP hydrolysis activity of purified ZntA was recently characterised and showed a specificity for Cd(II), Pb(II) and Zn(II). zntA expression has been reported to be up-regulated primarily by Zn(II), mediated by the regulatory protein ZntR, belonging to the MerR transcriptional regulator family. In contrast to previous claims, we now show, using a Phi(zntA-lacZ) monolysogen, that Cd(II) is the most effective inducer of zntA, which is also induced significantly by Pb(II). The Cd(II)- and Pb(II)-dependent transcriptional up-regulation of zntA is also mediated by ZntR.
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PMID:Cd(II), Pb(II) and Zn(II) ions regulate expression of the metal-transporting P-type ATPase ZntA in Escherichia coli. 1080 61

Analysis of the transport functions of individual Candida albicans plasma membrane drug efflux pumps is hampered by the multitude of endogenous transporters. We have stably expressed C. albicans Cdr1p, the major pump implicated in multiple-drug-resistance phenotypes, from the genomic PDR5 locus in a Saccharomyces cerevisiae mutant (AD1-8u(-)) from which seven major transporters of the ATP-binding cassette (ABC) family have been deleted. High-level expression of Cdr1p, under the control of the S. cerevisiae PDR5 promoter and driven by S. cerevisiae Pdr1p transcriptional regulator mutation pdr1-3, was demonstrated by increased levels of mRNA transcription, increased levels of nucleoside triphosphatase activity, and immunodetection in plasma membrane fractions. S. cerevisiae AD1-8u(-) was hypersensitive to azole antifungals (the MICs at which 80% of cells were inhibited [MIC(80)s] were 0.625 microg/ml for fluconazole, <0.016 microg/ml for ketoconazole, and <0.016 microg/ml for itraconazole), whereas the strain (AD1002) that overexpressed C. albicans Cdr1p was resistant to azoles (MIC(80)s of fluconazole, ketoconazole, and itraconazole, 30, 0.5, and 4 microg/ml, respectively). Drug resistance correlated with energy-dependent drug efflux. AD1002 demonstrated resistance to a variety of structurally unrelated chemicals which are potential drug pump substrates. The controlled overexpression of C. albicans Cdr1p in an S. cerevisiae background deficient in other pumps allows the functional analysis of pumping specificity and mechanisms of a major ABC transporter involved in drug efflux from an important human pathogen.
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PMID:Functional expression of Candida albicans drug efflux pump Cdr1p in a Saccharomyces cerevisiae strain deficient in membrane transporters. 1170 10


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