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

The mutation of serine-174 to phenylalanine that causes a defect in the Escherichia coli F1-ATPase beta-subunit is suppressed by further mutations; Gly-149 to Ser, Ala-295 to Thr, Ala-295 to Pro, or Leu-400 to Gln (Miki, J., Fujiwara, K., Tsuda, M., Tsuchiya, T. and Kanazawa, H. (1990) J. Biol. Chem. 265, 21567-21572). We analyzed the effects of these second site mutations and of a newly identified Asn-158 to Tyr mutation on the activities of the ATPase without the original Ser-174 to Phe mutation. The beta-subunit with each amino acid replacement was expressed in the mutant strain JP17, which does not have a beta-subunit. Cells transformed with the plasmid carrying Ala-295 to Pro mutation alone did not grow on minimal medium agar supplemented with succinate as the sole carbon source, and showed 3% of the wild-type ATPase activity, suggesting that this mutation caused structural alterations affecting the catalytic function of the enzyme. Conversely transformants with other mutations grew well and had higher ATPase activities, suggesting that these mutations did not cause extensive structural alterations. From the transformants with the plasmid carrying the Ala-295 to Pro mutation, seven revertants capable of cell growth on succinate plates were isolated and reversion mutations were identified at residues 140, 159, 166, 171, 172 and 184 of the beta-subunits. The results suggested that Ser-174 and Ala-295 do not necessarily interact directly, but that the regions including these suppression mutation sites close to Ser-174, and Ala-295 interact with each other for the proper functioning of the ATPase. The ternary structure of the region surrounded by the residues which were identified as the reversion mutation sites for Ser-174 to Phe and Ala-295 to Pro mutations is important for the catalytic function of this enzyme.
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PMID:Residues interacting with serine-174 and alanine-295 in the beta-subunit of Escherichia coli H(+)-ATP synthase: possible ternary structure of the center region of the subunit. 806 Oct 38

Nucleotide binding proteins, including ras, elongation factor Tu, adenylate kinase, and the mitochondrial F1-ATPase have a glycine-rich motif known as the P-loop or the Walker A sequence (Walker, J. E., Saraste, M., Runswick, M. J., and Gay, N. J. (1982) EMBO J. 1, 945-951). The primary structural constraints have been determined in the P-loop located in the beta-subunit of the mitochondrial ATPase from yeast. The primary structural constraints were determined for 9 residues that form the P-loop, 190Gly-Gly-Ala-Gly-Val-Gly-Lys-Thr-Val198. Each residue was tested individually for possible functional replacements while keeping the primary structure of the remainder of the molecule constant. This analysis indicates with greater than 95% confidence that Gly190,Gly195, and Lys196 are invariant and Thr197 can only be replaced with Ser. The most alterable residue is Gly191, where 10 replacements, even Phe, form a functional enzyme. The remaining positions allow some amino acid replacements while restricting others. The primary structural constraints of the P-loop of the mitochondrial F1 suggests that the three-dimensional structure of the P-loop is similar to that of ras.
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PMID:Primary structural constraints of P-loop of mitochondrial F1-ATPase from yeast. 814 26

The sequence (Gly-X-X-X-X-Gly-Lys-Thr/Ser) is conserved in nucleotide binding proteins including the alpha and beta subunits of the ATP synthase. Various mutations were introduced in the alpha Lys-175 and alpha Thr-176 residues in the sequence (Gly-Asp-Arg-Gln-Thr-Gly-Lys-Thr, residues 169-176) of the Escherichia coli ATP synthase alpha subunit. Surprisingly, single amino acid substitutions drastically affected the subunit assembly of the enzyme. The entire enzyme assembly was lost by alpha Lys-175-->Phe (or Trp) or alpha Thr-176-->Phe (or Tyr) mutation. Other mutants had similar (alpha His-175, alpha Ser-175, alpha Gly-175, alpha Ser-176, and alpha His-176 mutants) or lower (alpha Ala-176, alpha Cys-176, alpha Leu-176, and alpha Val-176 mutants) effects on assembly of the active enzyme compared with that of the wild-type. However, all these mutant enzymes except the alpha Ser-176 enzyme showed enhanced cold sensitivities and reduced stabilities at high temperature. Mutant enzymes such as alpha Gly-175 and alpha His-176 showed low multi-site (steady state) catalysis, possibly due to loss of proper subunit-subunit interactions. These results suggest that the alpha Lys-175 and alpha Thr-176 residues are not absolutely essential for catalysis, but that they, or possibly the entire conserved sequence, are located in the key domain for the subunit-subunit interactions essential for enzyme stability and steady state activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The alpha subunit of ATP synthase (F0F1): the Lys-175 and Thr-176 residues in the conserved sequence (Gly-X-X-X-X-Gly-Lys-Thr/Ser) are located in the domain required for stable subunit-subunit interaction. 826 95

The a subunit of F1F0 ATP synthase contains a highly conserved region near its carboxyl terminus which is thought to be important in proton translocation. Cassette site-directed mutagenesis was used to study the roles of four conserved amino acids Gln-252, Phe-256, Leu-259, and Tyr-263. Substitution of basic amino acids at each of these four sites resulted in marked decreases in enzyme function. Cells carrying a subunit mutations Gln-252-->Lys, Phe-256-->Arg, Leu-259-->Arg, and Tyr-263-->Arg all displayed growth characteristics suggesting substantial loss of ATP synthase function. Studies of both ATP-driven proton pumping and proton permeability of stripped membranes indicated that proton translocation through F0 was affected by the mutations. Other mutations, such as the Phe-256-->Asp mutation, also resulted in reduced enzyme activity. However, more conservative amino acid substitutions generated at these same four positions produced minimal losses of F1F0 ATP synthase. The effects of mutations and, hence, the relative importance of the amino acids for enzyme function appeared to decrease with proximity to the carboxyl terminus of the a subunit. The data are most consistent with the hypothesis that the region between Gln-252 and Tyr-263 of the a subunit has an important structural role in F1F0 ATP synthase.
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PMID:Mutagenic analysis of the a subunit of the F1F0 ATP synthase in Escherichia coli: Gln-252 through Tyr-263. 838 11

The beta Gly-149 residue is in a glycine-rich sequence (Gly-Gly-Ala-Gly-Val-Gly-Lys-Thr; residues 149-156) of the Escherichia coli H(+)-ATPase (ATP synthase) beta subunit. Substitution of beta Gly-149 by Ser suppressed the effect of the beta Ser-174-->Phe mutation (Iwamoto, A., Omote, H., Hanada, H., Tomioka, N., Itai, A., Maeda, M., and Futai, M. (1991) J. Biol. Chem. 266, 16350-16355), suggesting that beta Gly-149 is located near beta Ser-174. In this study, we introduced different residues at position 149 and found that a single mutant beta Cys-149 was defective. The effect of beta Cys-149 mutation was suppressed by beta Gly-172-->Glu, beta Ser-174-->Phe, beta Glu-192-->Val, or beta Val-198-->Ala replacement. These results suggest that beta Gly-149, beta Gly-172, beta Ser-174, beta Glu-192, and beta Val-198 residues are located close together in the catalytic site. From these findings we propose a model of the catalytic site of the enzyme near the gamma phosphate moiety of ATP. F1 enzymes with the double mutations beta Cys-149/beta Glu-172, beta Cys-149/beta Phe-174, beta Cys-149/beta Val-192, and beta Cys-149/beta Ala-198 were less sensitive than wild-type F1 to dicyclohexylcarbodiimide and adenosine triphosphopyridoxal (an affinity analogue of ATP forming a Schiff base with the epsilon-amino group of beta Lys-155 or beta Lys-201), and became sensitive to N-ethylmaleimide in an ATP-protected manner. These results of inhibitor studies are consistent with the proposed model.
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PMID:Domains near ATP gamma phosphate in the catalytic site of H+-ATPase. Model proposed from mutagenesis and inhibitor studies. 842 92

Synthesis of [14C]dequalinium, 1,1'-(1,10-[1,10-14C]decanediyl)bis[4-amino-2-methylquinolinium ], is described, which photoinactivates the bovine heart mitochondrial F1-ATPase (MF1). Maximal photoinactivation occurs on incorporation of about 1.5 mol of [14C]dequalinium/mol of MF1. Three radioactive species were resolved when photoinactivated enzyme was submitted to polyacrylamide gel electrophoresis at pH 4.0 in the presence of tetradecyltrimethylammonium bromide, which correspond to the alpha and beta subunits and a cross-linked species with an M(r) of 116,000. Fractionation of a tryptic digest of photoinactivated enzyme by high-performance liquid chromatography led to isolation of a radioactive peptide which contains residues 399-420 of a alpha subunit. Two fragments containing equal amounts of radioactivity were obtained on fractionation of an endoproteinase Asp-N digest of the isolated radioactive tryptic peptide by high-performance liquid chromatography. Amino acid sequence analysis showed that both fragments contained residues 399-408 of the alpha subunit, but one was missing Phe-alpha 403 and the other was lacking Phe-alpha 406. Fractionation of a cyanogen bromide digest of photoinactivated enzyme followed by trypsin digestion of partially purified cyanogen bromide fragments and fractionation of the resulting radioactive tryptic fragments yielded several radioactive species comprised of residues 399-420 of the alpha subunit cross-linked to residues 440-459 of the beta subunit and a radioactive fragment containing residues 399-420 of the alpha subunit. Partial sequence analyses of the cross-linked fragments suggest that Phe-alpha 403 and Phe-alpha 406 participate in cross-links, whereas no information was obtained on the site or sites of cross-linking in the beta subunit fragment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Photoinactivation of the bovine heart mitochondrial F1-ATPase by [14C]dequalinium cross-links phenylalanine-403 or phenylalanine-406 of an alpha subunit to a site or sites contained within residues 440-459 of a beta subunit. 844 63

The Atp11p protein of Saccharomyces cerevisiae is required for proper assembly of the F1 component of the mitochondrial ATP synthase. The mutant atp11 genes were cloned and sequenced from 12 yeast strains, which are respiratory-deficient due to a defect in Atp11p function. Four of the mutations mapped to the mitochondrial targeting domain (amino-terminal 39 amino acids) of Atp11p. All the genetic lesions found in the mature protein sequence were shown to be nonsense mutations. This result is consistent with the idea that Atp11p activity is provided, principally, by the overall structure of a functional domain, and not by specific amino acid residues in a localized active site. Amino-terminal (Edman) sequence analysis of fragments derived from limited proteolysis of purified Atp11p, and in vivo functional characterization of deletion mutants, were employed to locate the position of the active region in the protein. Three domains, separated by proline-rich sequences, were identified in the mature protein. The active domain of Atp11p was mapped to the sequence between Phe-120 and Asn-174. The domains proximal (Glu-40 through Ser-109) and distal (Arg-183 through Asn-318) to the active region were found to be important for the protein stability inside mitochondria.
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PMID:Identification of functional domains in Atp11p. Protein required for assembly of the mitochondrial F1-ATPase in yeast. 861 60

In the absence of an electrochemical proton gradient, the F1 moiety of the mitochondrial ATP synthase catalyzes the hydrolysis of ATP. This reaction is inhibited by a natural protein inhibitor, in a process characterized by an increase in ATPase inhibition as pH is decreased from 8.0 to 6.0. In order to gain greater insight into the molecular and chemical events underlying this regulatory process, the relationships among pH, helicity of the inhibitor protein, and its capacity to inhibit F1-ATPase activity were examined. First, peptides corresponding to four regions of the 82-amino-acid inhibitor protein were chemically synthesized and assessed for both retention of secondary structure, and capacity to inhibit F1-ATPase activity. These studies showed that a region of only 24-amino-acid residues, from Phe 22 through Len 45, accounts for the inhibitory capacity of the inhibitor protein, and that retention of native helical structure in this region is not essential for inhibition. Second, three mutants (33P34, 39P40, and 43P44) of the intact inhibitor protein were prepared in which a proline residue was inserted within the inhibitory region to disrupt native helical structure. The secondary structures and inhibitory capacities of these mutants were analyzed as a function of pH. These studies revealed that, despite the initial loss of helical structure within the inhibitory region due to proline insertion, a further loss of helical structure is required to modulate inhibitory activity. These results suggest that a loss of helical structure outside the inhibitory region correlates with an increase in inhibitory capacity. Finally, two separate mutants (H48A and H55A) were prepared in which a conserved histidine residue in the wild-type inhibitor protein was replaced with an alanine. The secondary structures and inhibitory capacities of these mutants were also investigated as a function of pH. Results indicated that, although histidine residues do not directly affect the inhibitory capacity of the protein, they are important for maintaining the inhibitor protein in an inactive form at high pH. Furthermore, these results show that loss in helical structure, although correlated with an increase in inhibitory capacity, is not essential for this function. These novel experiments are consistent with a model in which the inhibitor protein is envisioned as consisting of two regions, an inhibitory region and a regulatory region. It is suggested that reduction of pH allows for the protonation of a histidine residue blocking the interaction between the two regions, thus activating the inhibitory response. The pH reduction also correlates with a partial unfolding of the protein that may either cause or result from the loss of interaction between the two helices. This unfolding may be necessary for further optimization of inhibitor function.
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PMID:Protein inhibitor of mitochondrial ATP synthase: relationship of inhibitor structure to pH-dependent regulation. 866 Jun 64

Residue beta-V198 of the yeast mitchondrial F1-ATPase abuts the P-loop motif and the side chain is within 3.8 A of the nucleotide as shown in the crystal structure of the bovine ATPase [J. P. Abrahams, A. G. W. Leslie, R. Lutter, and J. E. Walker (1984) Nature 370,621-628]. This study has made and analyzed 17 replacements of V198 to understand the importance of the side chain in the nucleotide binding site. In addition, a suppressor of V198S, beta-L390F, was studied in the presence of various replacements at position 198. In vivo and in vitro analyses indicate that the Val side chain is critical for forming a stable and active enzyme. Biochemical analysis of mitochondria isolated from the mutant strains indicates that amino acids with hydrophobic side chains are the most effective replacements. In addition, size is important, but a large side chain can be largely compensated for until the size reaches that of the Phe and Trp. A methyl group is the minimal side chain necessary for function, as the beta-subunit is not stable in vivo with Gly at position 198. These results indicate that V198 forms critical hydrophobic interactions with the adenine ring of the nucleotide.
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PMID:Mutagenesis of beta-V198 in the F1-ATPase of yeast Saccharomyces cerevisiae and its role in binding nucleotide. 899 Feb 64

Cystic fibrosis is a human monogenic genetic disease caused by mutations in the cystic fibrosis (CF) gene, which encodes a membrane protein which functions as a channel: the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most frequent mutation, a deletion of phenylalanine F508 (delta F508), is located in the first nucleotide binding domain of CFTR: NBF1. This mutation leads to a folding defect in NBF1, responsible for an incomplete maturation of CFTR. The absence of CFTR at the surface of epithelial cells causes the disease. Determination of the three-dimensional (3D) structure of NBF1 is a key step to understanding the alterations induced by the mutation. In the absence of any experimental data, we have chosen to build a 3D model for NBF1. This model was built by homology modelling starting from F1-ATPase, the only protein of known 3D structure in the ATP binding cassette (ABC) family. This new model defines the central and critical position of F508, predicted in the hydrophobic core of NBF1. F508 indeed could be involved in hydrophobic interactions to ensure a correct folding pathway. Moreover, this model enables the localization of the LSGGQ sequence (a highly conserved sequence in the ABC family) in a loop, at the surface of the protein. This reinforces the hypothesis of its role for mediation of domain-domain interactions of functional significance for the channel regulation. Finally, the model also allows redefinition of the ends of NBF1 within the CFTR sequence. These extremities are defined by the secondary structure elements that are involved in the NBF1 fold. They lead to reconsideration of the C-terminal limit which was initially defined by the end of exon 12.
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PMID:Insight into cystic fibrosis by structural modelling of CFTR first nucleotide binding fold (NBF1). 918 Nov 19


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