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 sequence of the 16,019 nucleotide-pair mitochondrial DNA (mtDNA) molecule of Drosophila yakuba is presented. This molecule contains the genes for two rRNAs, 22 tRNAs, six identified proteins [cytochrome b, cytochrome c oxidase subunits I, II, and III (COI-III), and ATPase subunits 6 and 8] and seven presumptive proteins (URF1-6 and URF4L). Replication originates within a region of 1077 nucleotides that is 92.8% A + T and lacks any open reading frame larger than 123 nucleotides. An equivalent to the sequence found in all mammalian mtCDNAs that is associated with initiation of second-strand DNA synthesis is not present in D. yakuba mtDNA. Introns are absent from D. yakuba mitochondrial genes and there are few (0-31) intergenic nucleotides. The genes found in D. yakuba and mammalian mtDNAs are the same, but there are differences in their arrangement and in the relative proportions of the complementary strands of the molecule that serve as templates for transcription. Although the D. yakuba small and large mitochondrial rRNA genes are exceptionally low in G and C and are shorter than any other metazoan rRNA genes reported, they can be folded into secondary structures remarkably similar to the secondary structures proposed for mammalian mitochondrial rRNAs. D. yakuba mitochondrial tRNA genes, like their mammalian counterparts, are more variable in sequence than nonorganelle tRNAs. In mitochondrial protein genes ATG, ATT, ATA, and in one case (COI) ATAA appear to be used as translation initiation codons. The only termination codon found in these genes is TAA. In the D. yakuba mitochondrial genetic code, AGA, ATA, and TGA specify serine, isoleucine, and tryptophan, respectively. Fifty-nine types of sense condon are used in the D. yakuba mitochondrial protein genes, but 93.8% of all codons end in A or T. Codon-anticodon interactions may include both G-A and C-A pairing in the wobble position. Evidence is summarized that supports the hypothesis that A and T nucleotides are favored at all locations in the D. yakuba mtDNA molecule where these nucleotides are compatible with function.
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PMID:The mitochondrial DNA molecular of Drosophila yakuba: nucleotide sequence, gene organization, and genetic code. 300 25

The purpose of this study was to determine if the metabolic response to obesity and to pair feeding of obese Zucker rats to lean Zucker rats was similar across skeletal muscles. Oxidation of glucose, palmitate and isoleucine was studied in muscle strips in vitro using appropriate 14- carbon substrates as tracers. The plantaris muscle was subjected to histochemical analyses using an alkaline actomyosin ATPase, NADH-tetrazolium reductase and an oil red 0 stain. Soleus muscles from both ad libitum and pair fed obese rats oxidized less glucose to CO2, but released similar amounts of lactate when compared to the soleus muscles of lean rats. Oxidation of glucose was similar in the extensor digitorum longus (EDL) muscle of ad libitum fed obese rats, but lower when pair fed to the intake of lean rats. No differences were apparent in palmitate oxidation to CO2 or in incorporation into lipid (both soleus and EDL muscles), except in the EDL muscle of pair-fed obese rats which exhibited a higher rate for palmitate metabolism when compared with lean rats. Isoleucine oxidation to CO2 was higher in the EDL and plantaris muscles, but similar in the soleus muscle of ad libitum-fed obese rats when compared with lean rats. The magnitude of the difference in isoleucine oxidation was similar when the obese rats were pair fed. No differences in the percentage of plantaris muscle fibers sensitive to alkaline ATPase staining were observed. The plantaris muscle of obese rats, contained a higher proportion of oxidative fibers. These results indicate the great risk in generalizing about metabolic activity of the whole skeletal muscle mass based on observations made on one, or even two, distinct muscles in this animal model. Also, pair feeding of obese to lean Zucker rats did not result in uniform changes in metabolism between muscles of the obese rats.
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PMID:Metabolic characteristics of skeletal muscle from lean and obese Zucker rats. 345 May 49

It is possible to select transmembrane potential (delta psi)-altered mutants in Streptococcus pneumoniae on the basis of their resistance to the antifolate methotrexate. Comparison of such a mutant strain ( amiA9 ) with its parent was used to evaluate the role of delta psi in the uptake of certain amino acids. The delta psi-dependent uptake of isoleucine, leucine, valine, and asparagine showed a reduced maximum velocity of uptake, and decrease in the transport constant of the energy-dependent, delta psi-independent uptake of lysine, methionine, and glutamine was observed. No reduction of the intracellular pool of ATP or of lactate excretion could be detected in the mutant strain. Moreover, studies on membrane preparations suggest that the phenotype expressed by the amiA mutation is not a consequence of alteration of its ATPase activity or susceptibility to N,N'-dicyclohexylcarbodiimide. Therefore, it is unlikely that the amiA mutation affects the H+ F1F0 ATPase which is involved in the establishment of the proton motive force in anaerobic bacteria. We propose that another function contributes to delta psi in S. pneumoniae. The amiA gene may be the structural gene of that function.
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PMID:Characterization of a Streptococcus pneumoniae mutant with altered electric transmembrane potential. 623 66

The structures and functions of the two alpha-actinin isoforms [R. Kobayashi et al. (1983) Eur. J. Biochem. 133, 607-611] isolated from rabbit longissimus dorsi and psoas muscles were compared. One-dimensional and two-dimensional electrophoretic analyses showed that the two alpha-actinins were different from each other in their subunit chain weights and isoelectric points. The Stokes' radius of the longissimus dorsi and psoas alpha-actinins was 7.4 nm and 7.0 nm, respectively. The amino acid analyses showed that, although the two alpha-actinins are similar in their amino acid compositions, longissimus dorsi alpha-actinin contains more aspartic acid and isoleucine than psoas alpha-actinin but fewer glycine and valine residues. Analysis of the soluble tryptic peptides by two-dimensional mapping revealed that the two alpha-actinins had major differences. These data suggested that the two isoforms are the products of at least two different genes. Despite these differences, both alpha-actinins share a number of common properties. Both alpha-actinins contain a 55-kDa peptide resistant to trypsin. The two proteins show no differences in actomyosin turbidity assays. ATPase assays and F-actin binding assays of alpha-actinin activity. Immunological examination indicates that the two alpha-actinins share antigenic determinants in common.
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PMID:Different muscle-specific forms of rabbit skeletal muscle alpha-actinin. 623 79

Subunit 9 (dicyclohexylcarbodiimide binding protein, 'proteolipid') of the mitochondrial F1F0-ATPase is a nuclearly coded protein in Neurospora crassa. It is synthesized on free cytoplasmic ribosomes as a larger precursor with an NH2-terminal peptide extension. The peptide extension is cleaved off after transport of the protein into the mitochondria. A processing activity referred to as processing peptidase that cleaves the precursor to subunit 9 and other mitochondrial proteins is described and characterized using a cell-free system. Precursor synthesized in vitro was incubated with extracts of mitochondria. Processing peptidase required Mn2+ for its activity. Localization studies suggested that it is a soluble component of the mitochondrial matrix. The precursor was cleaved in two sequential steps via an intermediate-sized polypeptide. The intermediate form in the processing of subunit 9 was also seen in vivo and upon import of the precursor into isolated mitochondria in vitro. The two cleavage sites in the precursor molecule were determined. The data indicate that: the correct NH2-terminus of the mature protein was generated, the NH2-terminal amino acid of the intermediate-sized polypeptide is isoleucine in position -31. The cleavage sites show similarity of primary structure. It is concluded that processing peptidase removes the peptide extension from the precursor to subunit 9 (and probably other precursors) after translocation of these polypeptides (or the NH2-terminal part of these polypeptides) into the matrix space of mitochondria.
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PMID:Processing peptidase of Neurospora mitochondria. Two-step cleavage of imported ATPase subunit 9. 623 9

The amino acid sequence of the proteolipid subunit of the ATP synthase was analyzed in six mutant strains from Escherichia coli K12, selected for their increased resistance towards the inhibitor N,N'-dicyclohexylcarbodiimide. All six inhibitor-resistant mutants were found to be altered at the same position of the proteolipid, namely at the isoleucine at residue 28. Two substitutions could be identified. In type I this residue was substituted by a valine resulting in a moderate decrease in sensitivity to dicyclohexylcarbodiimide. Type II contained a threonine residue at this position. Here a strong resistance was observed. These two amino acid substitutions did not influence functional properties of the ATPase complex. ATPase as well as ATP-dependent proton-translocating activities of mutant membranes were indistinguishable from the wild type. At elevated concentrations, dicyclohexylcarbodiimide still bound specifically to the aspartic acid at residue 61 of the mutant proteolipid as in the wild type, and thereby inhibited the activity of the ATPase complex. It is suggested that the residue 28 substituted in the resistant mutants interacts with dicyclohexylcarbodiimide during the reactions leading to the covalent attachment of the inhibitor to the aspartic acid at residue 61. This could indicate that these two residues are in close vicinity and would thus provide a first hint on the functional conformation of the proteolipid. Its polypeptide chain would have to fold back to bring together these two residues separated by a segment of 32 residues.
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PMID:Identification of amino-acid substitutions in the proteolipid subunit of the ATP synthase from dicyclohexylcarbodiimide-resistant mutants of Escherichia coli. 625 67

The photoautotrophic cyanobacterium Anacystis nidulans was used to investigate the membrane transport of branched-chain, neutral amino acids and its dependence on photosynthetic reactions. The uptake of alpha-amino [1-14C]isobutyric acid and L-[1-14C]leucine followed Michaelis, Menten kinetics and resulted in an energy-dependent accumulation. As in bacteria, different uptake systems for neutral amino acids were present: two DAG (D-alanine, aminoisobutyric acid, and glycine) systems responsible for uptake of alpha-amino [1-14C]isobutyric acid, and one LIV (leucine, isoleucine, and valine) system, responsible for uptake of leucine. The low-affinity DAG system seemed to be dependent on the presence of Na+ ions. Uptake was enhanced by white light and by monochromatic light of 630 nm. In far red light (717 nm) with and without nitrogen flushing, considerable uptake dependent on light intensity and inhibition by dibromothymoquinone and by high concentrations of KCN were observed. Therefore, the energy generated by photosystem I reactions only could perform this membrane transport. The proton translocator carbonylcyanide m-chlorophenylhydrazone and N,N-dicyclohexylcarbodiimide as an ATPase inhibitor reduced amino acid uptake to a high degree. A pH dependence of aminoisobutyric acid and leucine uptake was obvious, with a maximum at pH 6 to 7 and some at a pH as high as 9.5. At higher pH, increasing concentrations of Na+ K+ and also of triphenylmethylphosphonium ions inhibited the transport of aminoisobutyric acid. These findings are consistent with the assumption that ATP from photosynthetic reactions drives a membrane-bound proton-translocating ATPase producing a proton motive force, consisting at higher pH chiefly in a delta psi amount, which promotes a secondary active H+ or Na+/amino acid symport carrier.
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PMID:Amino acid uptake and energy coupling dependent on photosynthesis in Anacystis nidulans. 680 40

Because of the conflicting conclusions that have been reached regarding the location of the two putative membrane-spanning segments from cysteine 911 through isoleucine 929 and from isoleucine 946 through cysteine 964 in the alpha subunit of native ovine Na+/K(+)-transporting ATPase, the disposition of lysine 943 with respect to the plane of the lipid bilayer was investigated. Sealed, right-side-out vesicles were modified with pyridoxal phosphate and Na[3H]BH4 in the presence and absence of saponin, a reagent that creates holes in the membranes. Modified alpha polypeptide was isolated, and digested with trypsin and chymotrypsin to release the desired peptides, QQGMK and QQGMK([3H]pyr)NK (where [3H]pyr designates the modification on lysine 943). These peptides, after cyclization of their amino-terminal glutamines, were isolated with an immunoadsorbent specific for the amino-terminal sequence pyroglutamyl-QGM-followed by high-pressure liquid chromatography on a C-18 reverse phase column. Comparisons were made of the extent of incorporation of radioactivity into lysine 943 between sealed vesicles and sealed vesicles pretreated with saponin. An increase in incorporation into lysine 943 of 5-fold to 18-fold was seen in vesicles pretreated with saponin prior to the modification with pyridoxal phosphate. This increase in incorporation is consistent with a cytoplasmic location for lysine 943. This conclusion places the residues on the carboxy-terminal side of the putative membrane-spanning segment from cysteine 911 through isoleucine 929 and the amino-terminal side of the putative membrane-spanning segment from isoleucine 946 through cysteine 964 in the ovine alpha subunit on the cytoplasmic side of the membrane.
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PMID:Topological disposition of lysine 943 in native Na+/K(+)-transporting ATPase. 762 20

A Kluyveromyces lactis strain resistant to ethidium bromide and deficient in potassium uptake was isolated. Studies on the proton-pumping activity of the mutant strain showed that a decreased H(+)-ATPase specific activity was responsible for the observed phenotypes. The putative K. lactis PMA1 gene encoding the plasma membrane H(+)-ATPase was cloned by its ability to relieve the potassium transport defect of this mutant and by reversing its resistance to ethidium bromide. Its deduced amino acid sequence predicts a protein 899 residues long that is structurally colinear in its full length to H(+)-ATPases cloned from different yeasts, except for the presence of a variable N-terminal domain. By PCR-mediated amplification, we identified a transition from G to A that rendered the substitution of the fully conserved methionine at position 699 by isoleucine. We attribute to this amino acid change the low capacity of the mutant H(+)-ATPase to pump out protons.
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PMID:Molecular cloning of the plasma membrane H(+)-ATPase from Kluyveromyces lactis: a single nucleotide substitution in the gene confers ethidium bromide resistance and deficiency in K+ uptake. 773 Feb 65

We isolated four azide-resistant secA mutants of Bacillus subtilis and found that all of them were the result of a single amino acid replacement of threonine 128 of SecA by alanine or isoleucine. In the presence of 1.5 mM sodium azide, cell growth and protein translocation of the wild-type strain were completely inhibited, but those of the azide-resistant mutant strains were not. Wild-type and two mutant SecA proteins were purified. Both the basal level and the elevated ATPase activity of the mutant SecA proteins were threefold higher than those of the wild-type SecA. The elevated ATPase activity of the SecA mutants was reduced upon the addition of 1.5 mM sodium azide by only 5-10% as compared with 40% for that of the wild-type. These results indicate that the elevated ATPase activity of the SecA mutants is resistant to sodium azide and that is also required for the protein translocation process of B. subtilis.
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PMID:Acquisition of azide-resistance by elevated SecA ATPase activity confers azide-resistance upon cell growth and protein translocation in Bacillus subtilis. 789 2


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