Disulfide linkage of the b and delta subunits does not affect the function of the Escherichia coli ATP synthase.
The ATP synthase of Escherichia coli is believed to act through a rotational mechanism in which the b(2)delta subcomplex holds the alphabeta hexamer stationary relative to the rotating gamma and epsilon subunits. We have engineered a disulfide bond between cysteines introduced at position 158 of the delta subunit and at a position just beyond the normal C-terminus of the b subunit. The formation of this disulfide bond verifies that the C-terminal region of b is proximal to residue 158 of delta. The disulfide bond does not affect the ability of the F(1)F(0) complex to hydrolyze ATP, couple ATP hydrolysis to the establishment of a proton gradient, or maintain a proton gradient generated by the electron transport chain. These results are consistent with a permanent association of b(2) with delta as suggested by the rotational model of enzyme function.
McLachlin
D T
DT
Department of Biochemistry, University of Western Ontario, London, Ontario, Canada N6A 5C1.
Dunn
S D
SD
D000255:Adenosine Triphosphate / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D006868:Hydrolysis; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D017494:Proton Pumps / Q000737:chemistry; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics; D013050:Spectrometry, Fluorescence
D003432:Cross-Linking Reagents; D004220:Disulfides; D010446:Peptide Fragments; D017494:Proton Pumps; D003300:Copper; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D005022:Ethyldimethylaminopropyl Carbodiimide; C029892:cupric chloride