Disease relevance of atpI

• Cloned atp genes for the proton-translocating ATPase of the obligate aerobe Bacillus megaterium have been demonstrated to be capable of complementing Escherichia coli ATPase (unc) mutants (Hawthorne, C. A., and Brusilow, W. S. A. (1986) J. Biol. Chem. 261, 5245-5248) [1].
• However, as in the related organism Rhodopseudomonas blastica, neither genes for components of F0, the membrane sector of ATP synthase, nor a homologue of the E. coli uncI gene are associated with this locus, as they are in E. coli [2].
• We have analyzed several new transducing phages and plasmids carrying various lengths of the DNA segments of the unc operon by complementation assay using 14 new unc- mutants and representatives of previously described strains which were made available to us [3].

High impact information on atpI

• We conclude that the replication fork usually proceeds counter-clockwise toward the unc operon in the earliest period of replication [4].
• 5. Either atpZ, atpI, or atpZI complemented the similar phenotype of a triple mutant of Salmonella typhimurium (MM281), which is deficient in Mg2+ uptake. atpZ and atpI, separately and together, increased the Mg2+-sensitive 45Ca2+ uptake by vesicles of an Escherichia coli mutant that is defective in Ca2+ and Na+ efflux [5].
• This plasmid transformed eight unc- strains to Unc+, including uncB402 and uncA401, but did not complement uncD11 or four other strains [3].
• Organization of unc gene cluster of Escherichia coli coding for proton-translocating ATPase of oxidative phosphorylation [3].
• Transducing phages carrying parts of the unc gene cluster were isolated: lambda uncA-9 and lambda glmS phages converted only some of the unc- mutants to the Unc+, as determined by complementation assays [3].

Chemical compound and disease context of atpI

• Genetic complementation between two mutant unc alleles (unc A401 and unc D409) affecting the Fl portion of the magnesium ion-stimulated adenosine triphosphatase of Escherichia coli K12 [6].
• Valinomycin plus potassium also caused a rapid decrease in the intracellular levels of ATP of normal E. coli cells, but had little if any effect on the ATP levels of two mutants of E. coli carrying lesions in the energy-transducing ATP complex (unc mutants) [7].
• The mutation in strain KW-1 leading to more rapid growth on lactose was cotransducible with the asn and unc loci, at 83 min on the E. coli genetic map [8].
• In Escherichia coli wild-type cells and in ATPase-deficient cells (unc mutants), glucose was found to be transported mainly by an ATP-driven system [9].
• Dicyclohexylcarbodiimide-resistant mutants of Escherichia coli were isolated and characterized In one mutant the unc genes and affects the membrane-integrated part of the ATP synthetase [10].

Biological context of atpI

• A method was developed to incorporate mutant unc alleles into plasmids [11].
• Partial diploid strains were prepared in which the uncB402 allele was incorporated into the plasmid and the new unc mutation into the chromosome, or vice versa [11].
• Complementation between the mutant unc alleles was indicated by growth on succinate, growth yields on glucose, ATP-dependent transhydrogenase activities, ATP-induced atebrin-fluorescence quenching and oxidative-phosphorylation measurements [11].
• Closely linked upstream of the ATP synthase subunit genes is an open reading frame denoted gene 1, which is equivalent to the uncI gene of Escherichia coli [12].
• No transcription start sites were detected up to 1,000 bp upstream of the atpIp promoter, neither were any transcription start sites detected within the cluster of the eight structural atp genes [13].

Anatomical context of atpI

• Linkage of the uncI gene to an efficient ribosome binding site (the translational initiation region of the uncE gene) resulted in 10-20-fold increased gene expression [14].
• Examination of the polypeptide composition of membranes from various unc mutants allowed a sequence for the normal assembly of the F1-F0 ATPase complex to be proposed [15].
• Mutant strains of Escherichia coli male cells defective in Ca2+,Mg2+-dependent ATPase (unc) were constructed and tested for their ability to form a complex between sex pili and the filamentous phage fd under conditions where either the membrane potential or the cellular concentration of ATP was lowered [16].

Associations of atpI with chemical compounds

• Induction of expression of the four unc genes by the addition of isopropyl-beta-D-thiogalactoside resulted in inhibition of growth [17].
• The resulting mutation AS12 had a polar effect on the unc operon: membranes of the mutant AS12 contained the dicyclohexylcarbodiimide-binding protein c and the protein a as sole subunits of the ATP synthase [18].
• For this purpose, cells in which the unc gene was inactivated were used so that the interconversion between the proton gradient and ATP is not possible, and the effect of agents, which specifically affect either of them, was tested on transport of ethidium in the intact cell [19].
• Yet both the membrane potential and the capacity to transport glutamine were depressed in the unc mutants by valinomycin and potassium [7].

Other interactions of atpI

• The 606 bp segment located between the gidB and the atpI genes contains no coding sequences [13].
• The in vivo expression of uncI, the first gene of the operon, was very low, at best 10 to 20 times less than the expression of uncB [20].
• To examine how the atp genes are expressed under different conditions of cell culture, atpI-lacZ operon fusions were constructed and analyzed in single copy on the bacterial chromosome or on low-copy-number plasmids [21].

Analytical, diagnostic and therapeutic context of atpI

• RT-PCR studies confirmed the alkaline pH induction of the F0 F1 operon and the existence of the atpI gene [22].
• Electron microscopy of the replicating molecules, after digestion with restriction endonucleases, showed that the replication fork proceeds exclusively counter-clockwise towards the unc operon [23].

References