F0 of ATP Synthase Is a Rotary Proton Channel

• Published in: The Journal of biological chemistry Vol. 277; no. 15; pp. 13281 - 13285
• Main Authors: Suzuki, Toshiharu, Ueno, Hiroshi, Mitome, Noriyo, Suzuki, Junko, Yoshida, Masasuke
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 12.04.2002; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111210200

Coupling of proton flow and rotation in the F0 motor of ATP synthase was investigated using the thermophilic Bacillus PS3 enzyme expressed functionally in Escherichia coli cells. Cysteine residues introduced into the N-terminal regions of subunits b and c of ATP synthase (bL2C/cS2C) were readily oxidized by treating the expressing cells with CuCl2 to form predominantly a b-c cross-link with b-b and c-c cross-links being minor products. The oxidized ATP synthases, either in the inverted membrane vesicles or in the reconstituted proteoliposomes, showed drastically decreased proton pumping and ATPase activities compared with the reduced ones. Also, the oxidized F0, either in the F1-stripped inverted vesicles or in the reconstituted F0-proteoliposomes, hardly mediated passive proton translocation through F0. Careful analysis using single mutants (bL2C or cS2C) as controls indicated that the b-c cross-link was responsible for these defects. Thus, rotation of the c-oligomer ring relative to subunit b is obligatory for proton translocation; if there is no rotation of the c-ring there is no proton flow through F0.