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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 unc (or atp) operon of Escherichia coli comprises eight genes encoding the known subunits of the proton-translocating ATP synthase (H+-ATPase) plus a ninth gene (uncI) of unknown function. The subunit stoichiometry of the H+-ATPase (alpha 3 beta 3 gamma 1 delta 1 epsilon 1 a1b2c10-15) requires that the respective unc genes be expressed at different rates. This review discusses the experimental methods applied to determining how differential synthesis is achieved, and evaluates the results obtained. It has been found that the primary level of control is translational initiation. The translational efficiencies of the unc genes are determined by primary and secondary mRNA structures within their respective translational initiation regions. The respective rates of translation are matched to the subunit requirements of H+-ATPase assembly. Finally, points of uncertainty remain and experimental strategies which will be important in future work are discussed.
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PMID:Expression of the unc genes in Escherichia coli. 289 71

Transcription termination factor rho from Escherichia coli is a homohexamer of 419 amino acid subunits and catalyzes an ATP-dependent release of nascent RNA transcripts. A rho monomer has three distinct domains functioning independently at the first approximation: the amino-terminal one quarter containing a primary RNA-binding site, the central 270-amino acids region constituting an ATP-binding domain with homologies to F1-ATPase, and the carboxy-terminal remainder with unknown function(s). To further delineate the structural and functional organizations of rho protein, we undertook its random mutagenesis using error-prone polymerase chain reactions with the carboxy-terminal 100-amino acid region chosen as the initial target. From 14 mutants identified, rho protein was purified and characterized in vitro. Of these, 11 mutants are defective in termination in vivo and show decreased activities in various partial functions examined: ATP binding; RNA binding; and ATPase activities dependent on three cofactors with decreasing efficacies, poly(C), lambda cro RNA and poly(U). A few of them are also affected in the putative secondary RNA-binding site that is functionally coupled to ATP hydrolysis. By contrast, the three other mutants are hyperactive in termination, poly(U)-dependent ATPase activity, and RNA interaction at the primary site. In these properties, the hyper-terminating mutants strikingly resemble the "super rho" mutant formerly found in the amino-terminal domain. Taken together, these findings indicate that the carboxy-terminal region plays a pivotal role in functionally coupling the RNA and ATP-binding domains, plausibly by acting as an interface for their interaction within or across individual subunits. In light of the reported X-ray crystallographic structure of F1-ATPase, we propose a model for the tertiary and quaternary structure of rho that is consistent with the observed mutational effects as well as a number of structural and functional properties characteristic of rho.
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PMID:Structural and functional dissections of transcription termination factor rho by random mutagenesis. 750 Mar 53

The DNA encoding the subunits of the ATP synthase (F1F0) of Streptomyces lividans 66 strain 1326 was identified using oligodeoxyribonucleotide probes derived from the N-terminal sequence of subunit gamma of the F1 complex. The complete nucleotide sequence of the operon was determined. The atp operon contains nine genes, atpIBEFHAGDC, encoding the eight structural components of the ATP synthase complex and the i protein, a polypeptide of unknown function. The gene order found is identical to that in other non-photosynthetic eubacteria. The determination of the N-terminal amino acid (aa) sequences of the F1 subunits alpha, beta, gamma, delta and epsilon allowed us to identify the translational start points and to define the primary structures of the proteins. The aa sequence deduced for subunit delta revealed an N-terminal extension of about 90 aa, which is not present in any delta subunit or OSCP (oligomycin sensitivity-conferral protein) of other species studied so far. The phylogenetic relationship of eu- and archaebacteria was investigated using sequencing data of the highly conserved beta subunit of different ATP synthases including that of S. lividans. The calculations revealed that S. lividans beta does not form a phylogenetic group together with the Gram+ taxa of low G+C contents, but is more closely related to the beta subunit of Rhodobacteria.
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PMID:The ATP synthase (F1F0) of Streptomyces lividans: sequencing of the atp operon and phylogenetic considerations with subunit beta. 782 15

A new procedure for the isolation of ATP synthase from bovine mitochondria has been developed, with the primary objective of producing enzyme suitable for crystallization trials. Proteins were extracted from mitochondrial membranes with dodecyl-beta-D-maltoside, and the ATP synthase was purified from the extract in the presence of the same detergent by a combination of ion-exchange and gel-filtration chromatography and ammonium sulphate precipitation. This simple and rapid procedure yields 20-30 mg of highly pure and monodisperse enzyme, evidently consisting of 14 different subunits, amongst them, in apparently stoichiometric amounts with the established subunits, subunit e, a recently discovered subunit of unknown function. The enzyme preparation has an oligomycin-sensitive ATP hydrolysis activity, and so the F1 domain is functionally associated with the membrane domain, F0. In contrast with the N-termini of some of the subunits of bovine mitochondrial F1-ATPase, those of the F1F0-ATP synthase are not degraded by proteolysis during the isolation procedure. This preparation therefore satisfies prerequisites for crystallization trials.
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PMID:F1F0-ATP synthase from bovine heart mitochondria: development of the purification of a monodisperse oligomycin-sensitive ATPase. 824 Feb 95

The sequences of the genes for the nine subunits of ATP synthase in the thermophilic cyanobacterium Synechococcus 6716 have been determined. The genes were identified by comparison of the encoded proteins with sequences of ATP synthase subunits in other species, and confirmed for subunits alpha, beta, delta and epsilon, by determining their N-terminal sequences. They are arranged at three separate loci. Six of them are in one cluster in the order a: c: b': b: delta: alpha, and those for the beta and epsilon subunits form a second and separate cluster. The gene for the gamma-subunit is at a third site. As in other bacteria, the gene for subunit a is immediately preceded by a gene coding for a small hydrophobic protein of unknown function, known as uncI in Escherichia coli. The gene orders in Synechococcus 6716 are related to the orders of ATP synthase genes in the plastid genomes of higher plants, and particularly of a red alga and a diatom. The sequences of the subunits are similar to those of chloroplast ATP synthase, the alpha, beta and c subunits being particularly well conserved. Differences in the primary structures of the Synechococcus 6716 and chloroplast gamma subunits probably underlie different mechanisms of activation of ATP synthase. The nucleotide sequences that are presented also contain 12 other open reading frames. One of them encodes a protein sequence related to the E. coli DNA repair enzyme, photolyase, and another codes for a protein that contains internal repeats related to sequences in the myosin heavy chain.
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PMID:Organization and sequences of genes for the subunits of ATP synthase in the thermophilic cyanobacterium Synechococcus 6716. 836 78

In an attempt to understand the molecular nature of Batten disease, we have examined the amino acid sequence of the affected CLN3 gene product (The International Batten Disease Consortium (1995) Cell 82, 949-957) and the site-specific mutations which give rise to the biological defect. Homology searches and molecular modeling have led to the development of a model for the folding and disposition of the protein, possibly within a mitochondrial membrane. High homology with a yeast protein of unknown function suggests a strong evolutionary conservation of function. We speculate that a possible role for the protein may be in chaperoning the folding/unfolding or assembly/ disassembly of other proteins, specifically subunit c of the mitochondrial ATP synthase complex.
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PMID:A model for Batten disease protein CLN3: functional implications from homology and mutations. 898 Jan 23

Buchnera aphidicola is an intracellular, non-cultivable prokaryotic symbiont of the aphid Schizaphis graminum. A 6.8-kilobase fragment from B. aphidicola was cloned and sequenced and was found to contain genes encoding for proteins of the ATP synthase. The order of the genes, atpBEFHAGDC, is identical to that found inEscherichia coli and many other prokaryotes. This genetic organization is different from that observed in organelles such as mitochondria and chloroplasts, in which the genes are partitioned between the organellar and nuclear genomes. One difference between B. aphidicola and E. coli was the absence of atpI, a gene of unknown function, which in E. coli precedes atpB. As is the case of many other prokaryotes, atpBEFHAGDC appears to constitute a single transcription unit. The detection in B. aphidicola of the genes encoding the ATP synthase as well as past observations indicating that this organism is capable of respiration are consistent with the utilization byB. aphidicola of a proton gradient for the generation of ATP.
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PMID:The (F1F0) ATP synthase of Buchnera aphidicola (endosymbiont of aphids): genetic analysis of the putative ATP operon. 921 81

Construction of a gene expression system in tobacco cultured cells (BY2) was studied. A 925 bp promoter fragment of a heat-shock protein gene (HSP18.2) of Arabidopsis thaliana showed clear heat-shock response of expression of the beta-glucuronidase (GUS) reporter gene in BY2 cells. Similar results were observed in a 500 mL flask and 3-L jar fermentor. Isolation of strong promoters in BY2 cells was tried. cDNA clones, in which the mRNA level is high in log-phase cells and the copy number in the genome is low, were isolated. These clones showed high homology with F1-ATPase (mitochondria type), elongation factor 1-alpha, and a gene with an unknown function of A. thaliana (clone 27), respectively. A 5'-flanking region of clone 27 showed 6.2 times the promoter activity of the CaMV35S promoter in BY2 cells. Three cDNA clones, which are expressed in the stationary growth phase of BY2 cells, were isolated by a differential screening. These clones showed high sequence homologies to alcohol dehydrogenase, pectin esterase, and extensin. Promoters of these genes will be useful in gene expression in high cell-density culture.
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PMID:Metabolic engineering of cultured tobacco cells. 1019 12

Northern epilepsy is an autosomal recessive childhood onset epilepsy syndrome, clinically characterized by generalized tonic-clonic seizures with onset at 5 to 10 years of age and subsequent slowly progressive mental deterioration. The patients may reach 50 or 60 years of age. A mutation responsible for the disease has recently been identified in a novel gene on chromosome 8p23, encoding a putative membrane protein with an unknown function. The present study, based on three autopsied patients, is the first neuropathological analysis of the disease, and showed intraneuronal accumulation of cytoplasmic autofluorescent granules. The granules were strongly stained by the Luxol fast blue, periodic acid-Schiff, and Sudan black B methods in paraffin sections, and were immunoreactive for subunit c of the mitochondrial ATP synthase and sphingolipid activator proteins A and D. The intraneuronal storage was highly selective: the third layer of the isocortex and the hippocampal CA2, CA3, and CA4 sectors were severely affected, while other layers of the isocortex, the CA1 sector, and the cerebellar cortex were only minimally involved. The membrane-bound storage cytosomes showed a curvilinear ultrastructure with admixture of some granular components. Western blotting and N-terminal sequence analysis of purified storage material identified subunit c as the major component. These findings establish Northern epilepsy as a new form of neuronal ceroid-lipofuscinosis with an exceptionally protracted course.
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PMID:Northern epilepsy: a novel form of neuronal ceroid-lipofuscinosis. 1076 41

Thorough analysis of the cta operon of Synechocystis sp. PCC6803 (grown in high-concentration salt medium to enhance the expression of respiratory proteins) showed that, apart from ctaCDE and Fb genes potentially encoding subunits I, II, III, and a small pseudo-bacteria-like subunit-IV of unknown function, a large mitochondria-like cta-Fm gene and a pronounced terminator structure are additional components of the operon. The deduced cta Fm gene product shows approximately 50% and 20% sequence identity to the Saccharomyces cerevisiae and beef heart mitochondrial COIV proteins, respectively. It also shows amino acid regions (near the N terminus, on the cytosolic side) with conspicuous sequence similarities to adenylate-binding proteins such as ATP synthase beta subunit Walker A and B consensus regions or to adenylate kinase. We suggest that, similar to the situation with beef heart mitochondria, it is the mitochondria-like subunit-IV of the cyanobacterial aa3-type cytochrome-c oxidase that confers allosteric properties to the cyanobacterial enzyme, the H+/e- ratios of cytochrome c oxidation being significantly lowered by ATP (intravesicular or intraliposomal) but enhanced by ADP. Therefore, the antagonistic action of ATP and ADP was in a way that the redox reaction proper, was always significantly less affected than the coupled proton translocation. Evolutionary and ecological implications of the unusual allosteric regulation of a prokaryotic cytochrome-c oxidase is discussed.
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PMID:Allosteric properties of cyanobacterial cytochrome c oxidase: inhibition of the coupled enzyme by ATP and stimulation by ADP. 1079 96


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