title: The number of accessible SH-groups in Escherichia coli membrane vesicles is increased by ATP or by formate.
abstract: The number of accessible SH-groups was determined in membrane vesicles prepared from Escherichia coli growing in fermentation conditions at slightly alkaline pH on glucose with or without added formate. Addition of ATP or formate to the vesicles caused a approximately 1.4-fold increase in the number of accessible SH-groups. The increase was inhibited by treatment with N-ethylmaleimide or the presence of the F(0)F(1)-ATPase inhibitors N,N(')-dicyclohexylcarbodiimide or sodium azide. The increase in accessible SH-groups was also absent in strains with the ATP synthase operon deleted or with the single F(0) domain cysteine Cysb21 changed to Ala. Using hyc and hyf mutants, it was shown that the increase was also largely dependent on hydrogenase 4 or hydrogenase 3, main components of formate hydrogen lyase, when bacteria were grown in the absence or presence of added formate. These results suggest a relationship between the F(0)F(1)-ATP synthase and hydrogenase 4 or hydrogenase 3 under fermentation conditions.
authors.affiliation: Department of Biophysics of the Biological Faculty, Yerevan State University, Armenia.
authors.forename: Nelli
authors.initials: N
authors.lastname: Mnatsakanyan
authors.forename: Anna
authors.initials: A
authors.lastname: Poladian
authors.forename: Karine
authors.initials: K
authors.lastname: Bagramyan
authors.forename: Armen
authors.initials: A
authors.lastname: Trchounian
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D022162:Cytoplasmic Vesicles / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry* / Q000187:drug effects / Q000201:enzymology; D029968:Escherichia coli Proteins; D005560:Formate Dehydrogenases / Q000235:genetics; D005561:Formates / Q000494:pharmacology*; D006864:Hydrogenase / Q000235:genetics; D009097:Multienzyme Complexes / Q000235:genetics; D009154:Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics; D013438:Sulfhydryl Compounds / Q000032:analysis*
chemical_list: D029968:Escherichia coli Proteins; D005561:Formates; D009097:Multienzyme Complexes; D013438:Sulfhydryl Compounds; C030544:formic acid; D000255:Adenosine Triphosphate; D006864:Hydrogenase; C455599:hydrogenase 4, E coli; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase; D006180:Proton-Translocating ATPases