title: Substitution of the cysteinyl residue (Cys21) of subunit b of the ATP synthase from Escherichia coli.
abstract: The Fo complex of the ATP synthase (F1Fo) of Escherichia coli contains only two cysteinyl residues, Cys21, of the two copies of subunit b. Modification of Cys21 with the hydrophobic maleimide N-(7-dimethylamino-4-methyl-coumarinyl)maleimide resulted in impairment of Fo functions [Schneider, E. & Altendorf, K. (1985) Eur. J. Biochim. 153, 105-109]. We replaced this residue (via cassette mutagenesis) by Ser, Gly, Ala, Thr, Asp and Pro. None of the replacements resulted in detectable alterations of the function of the ATP synthase, making a functional role for these sulfhydryl residues unlikely. Due to its high tolerance towards amino acid substitutions, the region around Cys21 seems not to be a protein-protein contact area.
authors.affiliation: Universität Osnabrück, Fachbereich Biologie/Chemie, Arbeitsgruppe Mikrobiologie, Federal Republic of Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kauffer
authors.forename: G
authors.initials: G
authors.lastname: Deckers-Hebestreit
authors.forename: K
authors.initials: K
authors.lastname: Altendorf
mesh_terms: D001483:Base Sequence; D003545:Cysteine; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D013050:Spectrometry, Fluorescence
chemical_list: D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D004024:Dicyclohexylcarbodiimide; D006180:Proton-Translocating ATPases; D003545:Cysteine