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

---

Query: EC:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Messenger RNA coding mitochondrial ATPase inhibitor protein, a small peptide comprised of 63 amino acid residues, was separated from a large quantity of mRNAs of larger molecules by high speed gel permeation chromatography. Messenger RNA coding a small stabilizing factor of inactivated F1F0-ATPase complex, which is also comprised of 63 amino acids, was recovered in the same fraction as the ATPase inhibitor, whereas mRNA for a large stabilizing factor with an apparent molecular weight of 15,000 was recovered in a fraction of slightly larger molecules. ATPase inhibitor precursor labeled with various kinds of radioactive amino acids was prepared separately by cell-free translation with the purified mRNA, and the amino terminal sequence of the precursor was examined. It was demonstrated that an extra peptide of 21 amino acid residues, including 5 leucine, 4 serine, 1 glycine, and 1 methionine residues, is located at the amino terminus of the ATPase inhibitor precursor.
...
PMID:Partial amino terminal sequence of the precursor of mitochondrial ATPase inhibitor protein synthesized with mRNA partially purified by gel permeation chromatography. 661 14

Residue beta-Met-209 is conserved in all known F1-ATPase sequences, and the mutation beta M209I in Escherichia coli causes profound inhibition of ATP synthesis and hydrolysis. Based on the properties of this mutant it had previously been proposed that residue beta-209 lies close to the site of catalysis. Two approaches were used to study this residue further. First, revertants were sought. Only wild-type and beta-Ser-209 were found; the Ser revertants involved a two-base change. Significantly, Ser is found at the equivalent position in the homologous vacuolar and archaebacterial ATPases. Second, all 20 natural amino acids were placed at position beta-209 by mutagenesis, and catalytic properties of the mutants were analyzed. The results showed that only a limited set of residues supported significant growth or ATPase activity, and that many of the mutations impacted severely on catalysis. X-ray structure analysis of the bovine enzyme has revealed that residue beta-Met-209 lies only 3.1. A from residue beta-Glu-181, which has been proposed to act as catalytic base. The results reported here emphasize that, in this discrete region of the catalytic site, specific stereo-chemical constraints on structure are critical for catalysis.
...
PMID:Mutagenesis and reversion analysis of residue Met-209 of the beta-subunit of Escherichia coli ATP synthase. 750 51

Deletion mutations in the NH2- and COOH-terminal regions of the epsilon subunit of Escherichia coli ATP synthase were constructed making use of the AatII and HincII restriction enzyme sites. The resultant mutated epsilon species were analyzed for in vivo functionality and for recognition by anti-epsilon monoclonal antibodies. Deletion of residues Asp-7 through Gln-14 (epsilon delta D7-Q14) resulted in reduced ability to complement uncC mutants as determined by growth yields on limiting glucose medium and by formation of small colonies on plates with succinate as the source of carbon and energy. None of the other mutants was notably impaired. Upon induction to obtain overexpression, the NH2-terminal deletion mutants were expressed at levels comparable to the wild-type epsilon subunit, but the COOH-terminal deletion mutants were expressed less strongly, suggesting that residues in the latter region are important for protein stability. Monoclonal antibody epsilon-1, which cannot bind to epsilon when it is part of F1-ATPase, recognized the COOH-terminal deletions well, but the NH2-terminal deletions poorly. Additional epitope mapping using epsilon fusion proteins revealed that residues required for the epsilon-1 epitope extend to between Thr-77 and Arg-85. Monoclonal antibody epsilon-4, which can bind to epsilon when it is part of F1-ATPase, recognized the NH2-terminal deletions well, but hardly recognized the COOH-terminal deletions, indicating a role of residues located COOH-terminal to Ile-131 in recognition by this antibody. Epitope mapping using the fusion proteins revealed that the residues required by epsilon-4 begin in the region between Val-78 and Met-95. These results imply a two-domain structure of epsilon and orient the subunit within the enzyme.
...
PMID:Orientation of the epsilon subunit in Escherichia coli ATP synthase. 768 93

A role in coupling proton transport to catalysis of ATP synthesis has been demonstrated for the Escherichia coli F0F1 ATP synthase gamma subunit. Previously, functional interactions between the terminal regions that were important for coupling were shown by finding several mutations in the carboxyl-terminal region of the gamma subunit (involving residues at positions 242 and 269-280) that restored efficient coupling to the mutation, gamma Met-23-->Lys (Nakamoto, R. K., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 867-872). In this study, we used suppressor mutagenesis to establish that the terminal regions can be separated into three interacting segments. Second-site mutations that cause pseudo reversion of the primary mutations, gamma Gln-269-->Glu or gamma Thr-273-->Val, map to an amino-terminal segment with changes at residues 18, 34, and 35, and to a segment near the carboxyl terminus with changes at residues 236, 238, 242, and 246. Each second-site mutation suppressed the effects of both gamma Gln-269-->Glu and gamma Thr-273-->Val, and restored efficient coupling to enzyme complexes containing either of the primary mutations. Mapping of these residues in the recently reported x-ray crystallographic structure of the F1 complex (Abrahams, J. P., Leslie, A. G., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628), reveals that the second-site mutations do not directly interact with gamma Gln-269 and gamma Thr-273 and that the effect of suppression occurs at a distance. We propose that the three gamma subunit segments defined by suppressor mutagenesis, residues gamma 18-35, gamma 236-246, and gamma 269-280, constitute a domain that is critical for both catalytic function and energy coupling.
...
PMID:The ATP synthase gamma subunit. Suppressor mutagenesis reveals three helical regions involved in energy coupling. 777 64

Five monoclonal antibodies against the alpha subunit of F1-ATPase from Escherichia coli alpha 104, alpha 105, alpha 107, alpha 109, and alpha 110 were prepared. The monoclonal antibodies alpha 104 and alpha 110 enhanced the F1-ATPase activity maximally to 1.6- and 1.7-fold that of the wild-type, respectively, while alpha 105 did not. Both antibodies bound to a peptide corresponding to the region between residues 354 and 513. Mutations in this region which caused reduced binding of the alpha subunit to the antibodies were identified at residues Ser-440, Leu-456, Leu-471, Leu-482, Met-483, and Ser-506 for alpha 104 and residues Ser-440, Leu-456, Leu-471, Asp-476, Leu-482, Met-483, and Ser-506 for alpha 110. These residues are possibly involved in the epitopes for the antibodies and are located close together on the surface of the alpha subunit. Among the mutations, Leu-456 to Pro and Ser-440 to Pro mutations caused increase of the F1-ATPase activity up to 1.9 and 1.2 times that of the wild-type, respectively, while Leu-471 to Pro mutation caused a defect in assembly of the F1-ATPase on the membrane. The other mutations caused no significant change in ATPase activity. These results suggested that Ser-440 and Leu-456 have an important role in regulating catalysis by the F1-ATPase, but that the neighboring residue Leu-471 has an important role in assembly of the F1-ATPase complex. It was also suggested that binding of the monoclonal antibodies alpha 104 and alpha 110 to residues Ser-440 and Leu-456 caused local conformational changes, leading to enhancing effects on F1-ATPase activity similar to the Ser-440 to Pro and Leu-456 to Pro mutations.
...
PMID:Enhancement of Escherichia coli H(+)-ATPase caused by binding of monoclonal antibodies is attributed to structural changes of Leu-456 and Ser-440 in the alpha subunit. 789 49

The mitochondrial F1-ATPase beta subunit (ATPase-beta) of Nicotiana plumbaginifolia is nucleus-encoded as a precursor containing an NH2-terminal extension. By sequencing the mature N. tabacum ATPase-beta, we determined the length of the presequence, viz. 54 residues. To define the essential regions of this presequence, we produced a series of 3' deletions in the sequence coding for the 90 NH2-terminal residues of ATPase-beta. The truncated sequences were fused with the chloramphenicol acetyl transferase (cat) and beta-glucuronidase (gus) genes and introduced into tobacco plants. From the observed distribution of CAT and GUS activity in the plant cells, we conclude that the first 23 amino-acid residues of ATPase-beta remain capable of specifically targeting reporter proteins into mitochondria. Immunodetection in transgenic plants and in vitro import experiments with various CAT fusion proteins show that the precursors are processed at the expected cleavage site but also at a cryptic site located in the linker region between the presequence and the first methionine of native CAT.
...
PMID:Truncated presequences of mitochondrial F1-ATPase beta subunit from Nicotiana plumbaginifolia transport CAT and GUS proteins into mitochondria of transgenic tobacco. 815 82

Irradiation of the F1-ATPase from Bacillus PS3 (TF1) in the presence of 134 microM 2-N3-[beta, gamma-32P]ATP plus Mg2+ for 90 min led to 95% inactivation of the ATPase activity which was accompanied by exclusive labeling of the beta subunit. The isolated alpha and beta subunits were also treated separately with 2-N3-[beta, gamma-32P]ATP under similar conditions. Fractionation of a tryptic digest of photolabeled TF1 by reversed-phase HPLC resolved a major and a minor radioactive peptide. Sequence analyses showed that the major peptide contained labeled Tyr-beta 364, whereas the minor one contained labeled Tyr-beta 341, residues known to be part of noncatalytic and catalytic sites, respectively. Two closely eluting radioactive peptides were obtained when a tryptic digest of the photolabeled, isolated beta subunit was fractionated by HPLC. Sequence analyses revealed that both contained labeled Tyr-beta 341. Fractionation of a tryptic digest of the photolabeled, isolated alpha subunit by HPLC resolved two peptides which contained the majority of the radioactivity incorporated. When subjected to eight cycles of automatic Edman degradation, one gave the sequence APGVXDR, corresponding to residues 133-139, in which X is a gap and corresponds to Met-alpha 137, which presumably is the derivatized residue. Only the first five cycles yielded phenylthiohydantoin derivatives when the other radioactive peptide derived from the alpha subunit was submitted to automatic Edman degradation which revealed the sequence APGVM, suggesting that Asp-alpha 138 is derivatized. The overall results suggest that the isolated beta subunit is a useful model for studying binding of nucleotides to catalytic sites, whereas the isolated alpha subunit may be of limited value in modeling interactions of nucleotides with noncatalytic sites.
...
PMID:Probing the specificity of nucleotide binding to the F1-ATPase from thermophilic Bacillus PS3 and its isolated alpha and beta subunits with 2-N3-[beta, gamma-32P]ATP. 816 Dec 17

The gamma subunit mutations, gamma Met-23-->Lys or Arg, in the Escherichia coli ATP synthase were previously reported to cause dramatically inefficient energy coupling between ATPase catalysis and H+ translocation (Shin, K., Nakamoto, R.K., Maeda, M., and Futai, M. (1992) J. Biol. Chem. 267, 20835-20839). In this paper, we report that second-site mutations in the gamma subunit can suppress the effects of gamma Met-23-->Lys. By screening randomly mutagenized uncG (gamma Met-23-->Lys), eight mutations in the carboxyl-terminal region were identified; strains carrying gamma Arg-242-->Cys, gamma Gln-269-->Arg, gamma Ala-270-->Val, gamma Ile-272-->Thr, gamma Thr-273-->Ser, gamma Glu-278-->Gly, gamma Ile-279-->Thr, or gamma Val-280-->Ala in combination with gamma Met-23-->Lys were able to grow by oxidative phosphorylation. H+ pumping assayed in membranes prepared from double mutation strains demonstrated that efficient ATP-dependent H+ transport was restored. Interestingly, the single mutations, gamma Gln-269-->Arg or gamma Thr-273-->Ser, caused reduced growth by oxidative phosphorylation; however, when these mutations were in combination with gamma Met-23-->Lys, growth was substantially increased. Furthermore, strains carrying gamma Met-23-->Lys, gamma Gln-269-->Arg, or gamma Thr-273-->Ser as single mutations were temperature sensitive, whereas, strains with the double mutations, gamma Met-23-->Lys/gamma Gln-269-->Arg or gamma Met-23-->Lys/gamma Thr-273-->Ser, were thermally stable. Taken together, these results strongly suggest that gamma Met-23, gamma Arg-242, and the region between gamma Gln-269 to gamma Val-280 are close to each other and interact to mediate efficient energy coupling.
...
PMID:The gamma subunit of the Escherichia coli ATP synthase. Mutations in the carboxyl-terminal region restore energy coupling to the amino-terminal mutant gamma Met-23-->Lys. 841 64

To study the assembly of mitochondrial F1F0 ATP synthase, cultured human cells were labeled with [35S]methionine in pulse-chase experiments. Next, two-dimensional electrophoresis and fluorography were used to analyze the assembly pattern. Two assembly intermediates could be demonstrated. First the F1 part appeared to be assembled, and next an intermediate product that contained F1 and subunit c. This product probably also contained subunits b, F6 and OSCP, but not the mitochondrially encoded subunits a and A6L. Both intermediate complexes accumulated when mitochondrial protein synthesis was inhibited, suggesting that mitochondrially encoded subunits are indispensable for the formation of a fully assembled ATP synthase complex, but not for the formation of the intermediate complexes. The results and methods described in this study offer an approach to study the effects of mutations in subunits of mitochondrial ATP synthase on the assembly of this complex. This might be of value for a better understanding of deficiencies of ATP synthase activity in mitochrondrial diseases.
...
PMID:Assembly of mitochondrial ATP synthase in cultured human cells: implications for mitochondrial diseases. 854 52

The interaction faces of the gamma and epsilon subunits in the Escherichia coli F1-ATPase have been explored by a combination of cross-linking and chemical modification experiments using several mutant epsilon subunits as follows: epsilonS10C, epsilonH38C, epsilonT43C, epsilonS65C, epsilonS108C, and epsilonM138C, along with a mutant of the gamma subunit, gammaT106C. The replacement of Ser-10 by a Cys or Met-138 by a Cys reduced the inhibition of ECF1 by the epsilon subunit, while the mutation S65C increased this inhibitory effect. Modification of the Cys at position 10 with N-ethylmaleimide or fluoroscein maleimide further reduced the binding affinity of, and the maximal inhibition by, the epsilon subunit. Similar chemical modification of the Cys at position 43 of the epsilon subunit (in the mutant epsilonT43C) and a Cys at position 106 of the gamma subunit (gammaT106C) also affected the inhibition of ECF1 by the epsilon subunit. The various epsilon subunit mutants were reacted with TFPAM3, and the site(s) of cross-linking within the ECF1 complex was determined. Previous studies have shown cross-linking from the Cys at positions 10 and 38 with the gamma subunit and from a Cys at position 108 to an alpha subunit (Aggeler, R., Chicas-Cruz, K., Cai, S. X., Keana, J. F. W., and Capaldi, R. A. (1992) Biochemistry 31, 2956-2961; Aggeler, R., Weinreich, F., and Capaldi, R. A. (1995) Biochim. Biophys. Acta 1230, 62-68). Here, cross-linking was found from a Cys at position 43 to the gamma subunit and from the Cys at position 138 to a beta subunit. The site of cross-linking from Cys-10 of epsilon to the gamma subunit was localized by peptide mapping to a region of the gamma subunit between residues 222 and 242. Cross-linking from a Cys at position 38 and at position 43 was with the C-terminal part of the gamma subunit, between residues 202 and 286. ECF1 treated with trypsin at pH 7.0 still binds purified epsilon subunit, while enzyme treated with the protease at pH 8.0 does not. This identifies sites around residue 70 and/or between 202 and 212 of the gamma subunit as involved in epsilon subunit binding.
...
PMID:Characterization of the interface between gamma and epsilon subunits of Escherichia coli F1-ATPase. 862 95


<< Previous 1 2 3 4 5 6 7 8 Next >>

---