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)

Chromatium vinosum contains a polypeptide that is functionally and structurally similar to the Escherichia coli chaperonin 10. The protein has been purified to homogeneity by sucrose density gradient centrifugation followed by gel filtration using a Bio-Gel A-1.5 m column. The molecular mass of chaperonin 10, as determined by gel filtration or nondenaturing polyacrylamide gel electrophoresis, is 95 kDa. The oligomer is composed of seven or eight subunits. Comparisons of the overall amino acid composition and N-terminal sequences among chaperonin 10 species from C. vinosum and E. coli reflect a high degree of similarity. A physical association between chaperonins 60 and 10 from C. vinosum, in vitro, is supported by three experimental approaches. First, the proteins form a stable binary complex in sucrose density gradients, gel filtration chromatography, and nondenaturing polyacrylamide gel electrophoresis, solely in the presence of ATP and Mg2+. Second, chaperonin 10 from C. vinosum binds, selectively, to a chaperonin 60-coupled Affi-Gel 10 matrix column. Third, a slight molar excess of chaperonin 10 is able to abolish, almost completely, the ATPase in chaperonin 60. The rate for ATPase activity of chaperonin 60 from C. vinosum is enhanced when supplemented with monovalent cations.
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PMID:Purification and characterization of chaperonin 10 from Chromatium vinosum. 134 70

GroEL140, a mutant Escherichia coli chaperonin unable to support bacteriophage lambda head assembly, was purified to near homogeneity and compared to wild type GroEL (cpn60). GroEL140 exhibited a 1.5-fold lower ATPase activity relative to the wild type protein. The hydrolysis of ATP by both polypeptides was fully inhibited by an excess of ATP gamma S and partially inhibited by ADP and 5'-adenylylimidodiphosphate, suggesting that adenine nucleotides display different affinities for the ATP binding site of chaperonins. GroEL140 was more sensitive to trypsin digestion compared to wild type GroEL indicating that the mutation destabilized the conformation of the mutant. The proteolytic susceptibility of both chaperonins was similarly enhanced upon addition of ATP, ADP or non-hydrolyzable ATP analogs, providing evidence (i) of a conformational change in the chaperonin structure which is likely to drive the protein discharge process, and (ii) that hydrolysis of ATP is not required to achieve topological modifications. GroEL140 retained its ability to bind non-native ribulose bisphosphate carboxylase/oxygenase (Rbu-P2-carboxylase), but released bound proteins upon addition of ATP and GroES (cpn 10) 6-7-fold less efficiently compared to GroEL. This functional defect was shown to be related to a suboptimal, but not an absence of, interaction with GroES since (i) GroEL140 and GroES were unable to form a complex isolatable by size exclusion chromatography, and (ii) increasing the incubation time or the concentration of GroES enhanced the amount of refolded Rbu-P2-carboxylase discharged from GroEL140-Rbu-P2-carboxylase binary complexes. Pulse-chase experiments involving a double immunoabsorption technique confirmed that Rbu-P2-carboxylase remained associated two times longer with GroEL140 than with GroEL in vivo.
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PMID:A mutation in GroEL interferes with protein folding by reducing the rate of discharge of sequestered polypeptides. 135 Jul 86

The mechanism of GroEL (chaperonin)-mediated protein folding is only partially understood. We have analysed structural and functional properties of the interaction between GroEL and the co-chaperonin GroES. The stoichiometry of the GroEL 14mer and the GroES 7mer in the functional holo-chaperonin is 1:1. GroES protects half of the GroEL subunits from proteolytic truncation of the approximately 50 C-terminal residues. Removal of this region results in an inhibition of the GroEL ATPase, mimicking the effect of GroES on full-length GroEL. Image analysis of electron micrographs revealed that GroES binding triggers conspicuous conformational changes both in the GroES adjacent end and at the opposite end of the GroEL cylinder. This apparently prohibits the association of a second GroES oligomer. Addition of denatured polypeptide leads to the appearance of irregularly shaped, stain-excluding masses within the GroEL double-ring, which are larger with bound alcohol oxidase (75 kDa) than with rhodanese (35 kDa). We conclude that the functional complex of GroEL and GroES is characterized by asymmetrical binding of GroES to one end of the GroEL cylinder and suggest that binding of the substrate protein occurs within the central cavity of GroEL.
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PMID:Chaperonin-mediated protein folding: GroES binds to one end of the GroEL cylinder, which accommodates the protein substrate within its central cavity. 136 Nov 69

An IgG1 monoclonal antibody (mAb 54G8) which binds to both Bordetella pertussis chaperonin-60 (cpn60) and Escherichia coli cpn60 (GroEL) was produced. mAb 54G8 as well as Fab fragments prepared from this antibody were found to abolish the ability of chaperonin-10 (cpn10, GroES) to inhibit the ATPase activity of both B. pertussis cpn60 and E. coli cpn60. Electron microscopy was used to localize the binding site of the monoclonal antibody on the B. pertussis cpn60 molecule. In the absence of the antibody, the B. pertussis molecule exhibited the tetradecameric structure typical of cpn60. Both end views (showing 7-fold symmetry of the face of the molecule) and side views were evident. When mAb 54G8 was bound, B. pertussis cpn60 molecules appeared to be cross-linked so that they formed long chains. Only side views of the molecules were seen in these long chains. When B. pertussis cpn60 complexed with Fab fragments of mAb 54G8 was examined, chains were no longer observed. Instead, side views of B. pertussis cpn60 were often seen with Fab fragments extending from the ends of the molecule. These data indicate that mAb 54G8 appears to bind at or near the end of the B. pertussis cpn60 molecule and that binding of mAb 54G8 at this location affects the ability of cpn10 to productively interact with cpn60, most likely either by sterically blocking the binding of cpn10, by affecting the conformation of cpn60 in such a way that it no longer binds cpn10, or by inhibiting proper transduction of the effects of cpn10 binding.
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PMID:Immunochemical localization of a region of chaperonin-60 important for productive interaction with chaperonin-10. 136 Nov 84

Incubation of tobacco and lettuce thylakoids with 2 M LiCl in the presence of MgATP removes the beta subunit from their CF1-ATPase (CF1 beta) together with varying amounts of the CF1 alpha subunit (CF1 alpha). These 2 M LiCl extracts, as with the one obtained from spinach thylakoids (Avital, S., and Gromet-Elhanan, Z. (1991) J. Biol. Chem. 266, 7067-7072), could form active hybrid ATPases when reconstituted into inactive beta-less Rhodospirillum rubrum chromatophores. Pure CF1 beta fractions that have been isolated from these extracts could not form such active hybrids by themselves, but could do so when supplemented with trace amounts (less than 5%) of CF1 alpha. A mitochondrial F1-ATPase alpha subunit was recently reported to be a heat-shock protein, having two amino acid sequences that show a highly conserved identity with sequences found in molecular chaperones (Luis, A. M., Alconada, A., and Cuezva, J. M. (1990) J. Biol. Chem. 265, 7713-7716). These sequences are also conserved in CF1 alpha isolated from various plants, but not in F1 beta subunits. The above described reactivation of CF1 beta by trace amounts of CF1 alpha could thus be due to a chaperonin-like function of CF1 alpha, which involves the correct, active folding of isolated pure CF1 beta.
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PMID:Reactivation of the chloroplast CF1-ATPase beta subunit by trace amounts of the CF1 alpha subunit suggests a chaperonin-like activity for CF1 alpha. 167 60

Two heat-shock proteins that show high identity with the Escherichia coli chaperonin 60 (groEL) and chaperonin 10 (groES) chaperonin proteins were purified and characterized from photolithoautotrophically grown Rhodobacter sphaeroides. The proteins were purified by using sucrose density gradient centrifugation and Mono-Q anion-exchange chromatography. In the presence of 1 mM ATP, the chaperonin 10 and chaperonin 60 proteins bound to each other and comigrated as a large complex during sucrose density gradient centrifugation. The native molecular weights of each protein as determined by gel filtration chromatography were 889,200 for chaperonin 60 and 60,000 for chaperonin 10. Chaperonin 60 is comprised of monomers with a molecular weight of 61,000 and chaperonin 10 is comprised of monomers with a molecular weight of 12,700 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Chaperonin 60 was 9.3% of the total soluble cell protein during photolithoautotrophic growth which increased to 28.5% following heat-shock treatment. When cells were grown photoheterotrophically or chemoheterotrophically, chaperonin 60 was reduced to 6.7% and 3.5%, respectively, of the total soluble protein. The N-terminal amino acid sequence of each protein was determined; chaperonin 60 of R. sphaeroides showed 72% identity to E. coli chaperonin 60 protein, and R. sphaeroides chaperonin 10 showed 45% identity with E. coli chaperonin 10. R. sphaeroides chaperonin 60 catalyzed ATP hydrolysis with a specific activity of 134 nmol min-1 mg-1 (kcat = 0.13 s-1) and was inhibited by R. sphaeroides chaperonin 10, but not E. coli chaperonin 10. The E. coli chaperonin 60 ATPase activity was inhibited by chaperonin 10 from both R. sphaeroides and E. coli.
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PMID:Purification and characterization of the chaperonin 10 and chaperonin 60 proteins from Rhodobacter sphaeroides. 167 80

A chaperonin has been purified from a thermophilic bacterium, Thermus thermophilus. It consists of two kinds of proteins with approximate Mr 58,000 and 10,000 and shows a 7-fold rotational symmetry from the top view and a "football"-like shape from the side view under the electron microscopic view. Its weak ATPase activity is inhibited by sulfite and activated by bicarbonate. ATP causes change of its mobility in nondenaturating polyacrylamide gel electrophoresis. The T. thermophilus chaperonin can promote in vitro refolding of several guanidine HCl-denatured enzymes from thermophilic bacteria. At high temperatures above 60 degrees C, where the native enzymes are stable but their spontaneous refoldings upon dilution of guanidine HCl fail, the chaperonin induces productive refolding in an ATP-dependent manner. No or very poor refolding is induced when the chaperonin is added to the solution aged after dilution. An excess amount of the chaperonin is inhibitory for refolding. At middle temperatures (30-50 degrees C), where spontaneous refoldings of the enzymes occur, the chaperonin arrests refolding in the absence of ATP and refolding is induced when ATP is supplemented. At temperatures below 20 degrees C, where spontaneous refoldings also occur, the chaperonin arrests the refolding but ATP does not induce refolding.
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PMID:A chaperonin from a thermophilic bacterium, Thermus thermophilus, that controls refoldings of several thermophilic enzymes. 168 19

The products of the Escherichia coli dnaK, dnaJ, and grpE heat shock genes have been previously shown to be essential for bacteriophage lambda DNA replication at all temperatures and for bacterial survival under certain conditions. DnaK, the bacterial heat shock protein hsp70 analogue and putative chaperonin, possesses a weak ATPase activity. Previous work has shown that ATP hydrolysis allows the release of various polypeptides complexed with DnaK. Here we demonstrate that the ATPase activity of DnaK can be greatly stimulated, up to 50-fold, in the simultaneous presence of the DnaJ and GrpE heat shock proteins. The presence of either DnaJ or GrpE alone results in a slight stimulation of the ATPase activity of DnaK. The action of the DnaJ and GrpE proteins may be sequential, since the presence of DnaJ alone leads to an acceleration in the rate of hydrolysis of the DnaK-bound ATP. The presence of GrpE alone increases the rate of release of bound ATP or ADP without affecting the rate of hydrolysis. The stimulation of the ATPase activity of DnaK may contribute to its more efficient recycling, and it helps explain why mutations in dnaK, dnaJ, or grpE genes often exhibit similar pleiotropic phenotypes.
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PMID:Escherichia coli DnaJ and GrpE heat shock proteins jointly stimulate ATPase activity of DnaK. 182 68

Both the chaperonin- and MgATP-dependent reconstitution of unfolded ribulosebisphosphate carboxylase (Rubisco) and the uncoupled ATPase activity of chaperonin 60 (groEL) require ionic potassium. The spontaneous, chaperonin-independent reconstitution of Rubisco, observed at 15 but not at 25 degrees C, requires no K+ and is actually inhibited by chaperonin 60, with which the unfolded or partly folded Rubisco forms a stable binary complex. The chaperonin-dependent reconstitution of Rubisco involves the formation of a complex between chaperonin 60 and chaperonin 10 (groES). Formation of this complex almost completely inhibits the uncoupled ATPase activity of chaperonin 60. Furthermore, although the formation of the chaperonin 60-chaperonin 10 complex requires the presence of MgATP, hydrolysis of ATP may not be required, since complex formation occurs in the absence of K+. The interaction of chaperonin 60 with unfolded or partly folded Rubisco does not require MgATP, K+, or chaperonin 10. However, discharge of the complex of chaperonin 60-Rubisco, which leads to the formation of active Rubisco dimers, requires chaperonin 10 and a coupled, K(+)-dependent hydrolysis of ATP. We propose that a role of chaperonin 10 is to couple the K(+)-dependent hydrolysis of ATP to the release of the folded monomers of the target protein from chaperonin 60.
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PMID:Chaperonin-facilitated refolding of ribulosebisphosphate carboxylase and ATP hydrolysis by chaperonin 60 (groEL) are K+ dependent. 197 61

The complete cDNA sequence of a mitochondrial protein from Chinese hamster ovary cells, designated P1, which was originally identified as a microtubule-related protein (Gupta, R.S., Ho, T.K.W., Moffat, M.R.K., and Gupta, R. (1982) J. Biol. Chem. 257, 1071-1078), has been determined. The P1 cDNA encodes a protein of 60,983 Da including a 26-amino acid putative mitochondrial targeting sequence at its N-terminal end. The deduced amino acid sequence of Chinese hamster P1 shows 97% identity to the human P1 protein. Most interestingly, the amino acid sequences of mammalian P1 proteins show extensive sequence homology (42-60% identical residues and an additional 15-25% conservative replacements) to the "chaperonin" family of bacterial, yeast, and plant proteins (viz. groEL protein of Escherichia coli, hsp 60 protein of yeast, and ribulose-1,5-bisphosphate carboxylase subunit binding protein of plant chloroplasts) and to the 60-65-kDa major antigenic protein of mycobacteria and Coxiella burnetii. The homology between mammalian P1 and other proteins begins after the putative mitochondrial presequence and extends up to the C-terminal end. Furthermore, similar to the chaperonin family of proteins, P1 appears to exist in cells as a homooligomeric complex of seven subunits and shows ATPase activity. These observations strongly indicate that P1 protein is a member of the chaperonin family and that it may be involved in a similar function in mammalian cells.
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PMID:Molecular cloning of a Chinese hamster mitochondrial protein related to the "chaperonin" family of bacterial and plant proteins. 256 57


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