Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have cloned and sequenced over 9 kb of the mitochondrial genome from the sea star Pisaster ochraceus. Within a continuous 8.0-kb fragment are located the genes for NADH dehydrogenase subunits 1, 2, 3, and 4L (ND1, ND2, ND3, and ND4L), cytochrome oxidase subunits I, II, and III (COI, COII, and COIII), and adenosine triphosphatase subunits 6 and 8 (ATPase 6 and ATPase 8). This large fragment also contains a cluster of 13 tRNA genes between ND1 and COI as well as the genes for isoleucine tRNA between ND1 and ND2, arginine tRNA between COI and ND4L, lysine tRNA between COII and ATPase 8, and the serine (UCN) tRNA between COIII and ND3. The genes for the other five tRNAs lie outside this fragment. The gene for phenylalanine tRNA is located between cytochrome b and the 12S ribosomal genes. The genes for tRNA(glu) and tRNA(thr) are 3' to 12S ribosomal gene. The tRNAs for histidine and serine (AGN) are adjacent to each other and lie between ND4 and ND5. These data confirm the novel gene order in mitochondrial DNA (mtDNA) of sea stars and delineate additional distinctions between the sea star and other mtDNA molecules.
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PMID:Nucleotide sequence of nine protein-coding genes and 22 tRNAs in the mitochondrial DNA of the sea star Pisaster ochraceus. 197 16

Using site-directed mutagenesis, Tyr-307, Tyr-341, or Tyr-364, supposedly located at the adenine nucleotide binding site(s) of the beta subunits of F1-ATPase from the thermophilic bacterium PS3, was replaced with Phe or Cys. The alpha 3 beta 3 complexes reconstituted from the alpha subunits and individual mutant beta subunits hydrolyzed ATP. Thus, neither the hydroxyl groups nor the aromatic rings in these positions are required for ATPase activity of F1-ATPase.
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PMID:Aromatic rings of tyrosine residues at adenine nucleotide binding sites of the beta subunits of F1-ATPase are not necessary for ATPase activity. 213 33

The ATP synthases of eubacteria and eukaryotes possess a conserved tyrosine (beta 331) that is labeled by ATP analogs and is believed to be at the catalytic site. In this report, this tyrosine was replaced by Phe, Ser, Cys, Gly, and Ala in an attempt to determine its role in catalysis. Each of the beta 331 mutant strains assembled an ATP synthase. Membranes from the beta 331-Ser, -Cys, -Ala, or -Gly strains showed strongly attenuated ATP hydrolysis and ATP-driven proton-pumping activities. The beta 331-Phe membranes showed nearly normal ATPase and functional proton pumping. A new purification procedure yielding highly active unc+ F1 (ATPase rates greater than 1000 s-1) allowed rapid isolation of soluble F1-ATPases. Kinetic analyses of purified enzymes confirmed that the structural and functional properties of beta 331-Tyr can be substituted by Phe but not effectively by Ser, Cys, Ala, or Gly. Since all of the beta 331 mutant enzymes catalyzed measurable ATP hydrolysis, it is clear that beta 331-Tyr is not directly involved in the bond making-breaking steps of catalysis. The ability of the beta 331-Phe enzyme to rapidly bind and hydrolyze ATP, and the results with other beta 331 mutant enzymes, suggests that a residue with an aromatic character is required at this position.
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PMID:Site-directed mutagenesis of the conserved beta subunit tyrosine 331 of Escherichia coli ATP synthase yields catalytically active enzymes. 214 32

Isolated human hepatocytes and separated neutrophils of 11 patients with alcoholic liver disease (ALD) were used to study some aspects of cellular calcium-related processes compared to nonalcoholic controls. 45Ca2+ efflux from the cells decreased in ALD and the calmodulin-inhibitor trifluoperazine did not influence it further. The intracellular free calcium concentration [( Ca2+]i) of nonstimulated hepatocytes and neutrophils proved to be higher in ALD with the Quin2/AM loading technique. However, the [Ca2+]i rise in hepatocytes and neutrophils, with stimulation by low density lipoprotein (LDL) and N-formyl-methionyl-leucyl phenylalanine (FMLP), respectively, was diminished in ALD compared to appropriate controls. The slower 45Ca2+ extrusion rate, higher basal [Ca2+]i levels, and the diminished [Ca2+]i elevation of activated hepatocytes and neutrophils, suggest disturbed calcium-related intracellular processes in ALD, in particular, impaired regulation of the plasma membrane Ca2(+)-ATPase.
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PMID:Disturbed intracellular calcium-related processes of hepatocytes and neutrophils in human alcoholic liver disease. 214 39

Simian virus 40 (SV40) mutant 5002 carries base pair substitutions of C-5109----T and C-5082----T. These mutations lie in a region of the genome that encodes amino acids common to the large and small viral tumor antigens (T and t antigens, respectively) and result in amino acid substitutions of Leu-19----Phe and Pro-28----Ser. In contrast to wild-type SV40, which produces large plaques that are clearly visible 8 days postinfection, mutant 5002 is defective for productive infection, producing tiny plaques that arise at around 21 days postinfection. However, 5002 is capable of replicating viral DNA and producing normal amounts of capsid proteins, indicating that the mutations alter an activity of T antigen that is required subsequent to DNA synthesis, such as maturation, viral assembly, or release of virions. The mutant T antigen has normal ATPase activity, is phosphorylated in a manner that is indistinguishable from that of the wild-type T antigen, and retains the ability to oligomerize. 5002 complements mutants defective in T antigen host range-adenovirus helper function for productive infection. Thus, T antigen encodes two activities that affect at least two different steps in viral infection other than DNA replication, one inactivated by mutations in the host range-adenovirus helper domain and one inactivated by the mutations present in 5002. The 5002-encoded T antigen is also defective for transformation of REF52 cells when expressed from the normal SV40 early promoter, although this defect can be partially overcome by expressing the protein from stronger promoters.
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PMID:A DNA replication-positive mutant of simian virus 40 that is defective for transformation and the production of infectious virions. 215 52

Pyridoxal 5'-diphospho-5'-adenosine (AP2PL) inhibits lamb kidney (Na,K)-ATPase and that inhibition and covalent modification is blocked by the presence of ATP. After trypsin digestion of the labeled, purified alpha subunit and subsequent peptide mapping of the fluorescently labeled peptides by means of high performance liquid chromatography, the main labeled peptide was further purified and analyzed by amino acid composition analysis and peptide sequencing. The obtained peptide had the sequence Ile470-Val-Glu-Ile-Pro-Phe-Asn-Ser-Thr-Asn-Lys480-Tyr-Gln-Le u-Ser-Ile-His- Lys487. Lysine 480 is the residue modified by AP2PL in the absence, but not in the presence of ATP. The beta subunit is not differentially labeled by AP2PL in the presence or absence of ATP. Interestingly, the same results were obtained using pyridoxal phosphate as the labeling and inactivation reagent, indicating that the specificity of labeling by these reagents is not due to the presence of the adenosine moiety, but instead that the initial recognition of nucleotides by the ATP-binding site of (Na,K)-ATPase may be due to recognition of the phosphate moiety. The amino acid sequence surrounding this lysine residue labeled by both reagents is highly conserved in (Na,K)-ATPase and the related (H,K)-ATPase sequences thus far obtained, which may signify a functional importance for this region of the putative ATP-binding site in these transport proteins.
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PMID:Lysine 480 is an essential residue in the putative ATP site of lamb kidney (Na,K)-ATPase. Identification of the pyridoxal 5'-diphospho-5'-adenosine and pyridoxal phosphate reactive residue. 216 43

In the midgut tissue of the silkworm, Bombyx mori, alkaline phosphatase isozymes, membrane-bound (m-ALP) and soluble (s-ALP) forms are controlled by non-allelic genes on the same chromosome. We purified and characterized both ALPs to elucidate their possible functions and to compare with mammalian ALPs. Both forms were found to be similar Mr = 68,000 in gel permeation chromatography and as a single subunit as a monomer in SDS-polyacrylamide gel electrophoresis with Mr = 58,000 for m-ALP and Mr = 61,000 for s-ALP. The pH optima of ALPs were 10.9 (m-ALP) and 9.8 (s-ALP), and the former was extremely stable even in pH 10-12 which accords with the physiological milieu in Bombyx midgut lumen. Both ALPs had similar substrate specificities. L-cysteine inhibited strongly both ALPs, but inhibitory effects of L-phenylalanine, L-homoarginine, and L-leucine were undetectable for s-ALP and very weak for m-ALP. The antibody raised against purified m-ALP recognized m-ALP but not purified s-ALP and vice versa. Rocket-immunoassay showed that m-ALP was distributed in similar levels along the length of midgut except for the most anterior portion. Seventy percent of s-ALP activity existed in the last one-third of midgut. Immunohistochemical study revealed that the m-ALP was localized at the brush border of columnar cells in the middle and posterior midgut epithelia. In contrast, the s-ALP was localized at the apical surface of goblet cells through the length of midgut. We detected ATPase activity in the purified s-ALP preparation; Mg2+ was essential for the ATPase activity and the activity also increased with KHCO3 but not with KCl. The solubilization test of m- ALP with various agents was attempted and the relationship between m-ALP and the digestive fluid-ALP was discussed.
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PMID:Genetically defined membrane-bound and soluble alkaline phosphatases of the silkworm: their discrete localization and properties. 239 71

The influence in vitro of SP and C-terminal fragments of analogues SP(5-11) (pyroGlu5, Tyr8); SP(6-11) (pyroGlu6, Tyr8); SP(6-11) (pyroGlu6, D-Phe7); SP(6-11) (pyroGlu6, D-Phe8) on the (Ca, Mg) and (Na, K) ATPases activities from synaptosomal membranes of cerebral cortex and hippocampus of rat brain were compared. The data obtained in this study indicate the following: 1. Substance P stimulates the activities of (Na, K) and (Ca, Mg) ATPases more effectively in synaptosomal membranes from hippocampus than cerebral cortex. 2. Heptapeptide SP(5-11) (pyroGlu5, Tyr8) causes a more distinct increase of (Ca, Mg) ATPase activity in cortical synaptosomal membranes than SP does. 3. The change of L-Phe conformation to D in position 7 in hexapeptide induces reduction of enzymes activities in hippocampus. 4. Especially important for the maintenance of biological activity of drugs is the replacement of Gln5 with pyroGlu6 and conformation of Phe residues. 5. SP and shorter analogues of fragments SP C-terminal SP regulate the active cation transport in synaptosomal membranes of cerebral cortex and hippocampus.
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PMID:A comparison of the effects of substance P and shorter analogues on the synaptosomal ATPases activities in the rat brain. 244 45

Four Escherichia coli mutants with defects in the alpha subunit of H+-ATPase (F0F1) (strain KF154, Pro-281----Leu; KF101 and KF131, Ala-285----Val; KF114, Arg-376----Cys) were isolated, and the kinetic properties of their F1-ATPases were studied. All the mutations so far identified are clustered in the two defined regions of the alpha subunit. With F1 of strain KF114, as with F1 of uncA401 (Ser-373----Phe; T. Noumi, M. Futai, and H. Kanazawa (1984) J. Biol. Chem. 259, 10076-10079), the rate of multisite hydrolysis of ATP was 4 X 10(-3)-fold lower than that with wild-type F1, suggesting that residues Ser-373 and Arg-376 or the regions in their vicinities are essential for positive catalytic cooperativity. With F1 from strain KF101, multisite hydrolysis was higher (about 40% of that of the wild type), but the F1 was unstable and showed defective interaction with the membrane sector (F0). The F1 from KF154 had lower multisite hydrolysis (about 10% of that of the wild type) but could support slow growth by oxidative phosphorylation.
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PMID:Mutational replacements of conserved amino acid residues in the alpha subunit change the catalytic properties of Escherichia coli F1-ATPase. 252 55

Pig gastric (H+ + K+)-ATPase can be covalently modified with pyridoxal 5'-phosphate (PLP) (about 1 mol/mol enzyme), and this modification is not observed in the presence of ATP, suggesting that PLP binds to a specific Lys residue in the ATP binding site or the region in its vicinity (Maeda, M., Tagaya, M., and Futai, M. (1988) J. Biol. Chem. 263, 3652-3656). The peptides labeled with radioactive PLP could be released from the gastric membrane vesicles quantitatively by chymotrypsin treatment, and two peptides were purified by high performance liquid chromatographies. These peptides were not obtained from vesicles incubated with PLP in the presence of ATP. The sequences of the two peptides were NH2-Asn-Ser-Thr-Asn-Lys-Phe-COOH and NH2-Ser-Thr-Asn-Lys-Phe-COOH, exactly corresponding to residues 493-498 and 494-498, respectively, of pig gastric (H+ + K+)-ATPase sequenced recently (Maeda, M., Ishizaki, J., and Futai, M. (1988) Biochem. Biophys. Res. Commun. 157, 203-209). Lys-497 was concluded to be the binding site of PLP, as pyridoxyl-Lys was identified at the corresponding position. This Lys residue is conserved in (Na+ + K+)- and Ca2+-ATPases. The possible amino acid residues in the catalytic site of gastric (H+ + K+)-ATPase are discussed.
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PMID:Pig gastric (H+ + K+)-ATPase. Lys-497 conserved in cation transporting ATPases is modified with pyridoxal 5'-phosphate. 252 82


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