Open AccessSubstitution of the cysteinyl residue (Cys21) of subunit b of the ATP synthase from Escherichia coli
Author(s) -
KAUFFER Sabine,
DECKERSHEBESTREIT Gabriele,
ALTENDORF Karlheinz
Publication year - 1991
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1991.tb16504.x
Subject(s) - atp synthase , maleimide , escherichia coli , residue (chemistry) , protein subunit , biochemistry , cysteine , chemistry , mutagenesis , enzyme , biology , stereochemistry , mutation , gene , organic chemistry
The F o complex of the ATP synthase (F 1 F o ) of Escherichia coli contains only two cysteinly 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 F o functions [Schneider, E. & Altendorf, K. (1985) Eur. J. Biochem. 153 , 105–109]. We replaced this resdue (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.