Stability and functionality of cysteine‐less FOF1 ATP synthase from Escherichia coli

Abstract
All 21 native cysteines in the Escherichia coli FOF1 ATP synthase were replaced by alanines. In isolated E. coli membranes, ATP‐dependent proton pumping, turnover of ATP hydrolysis and steady‐state transition state thermodynamic parameters of the cysteine‐less enzyme were similar to wild‐type. The cysteine‐less enzyme was solubilized in n‐octyl β‐d‐glucopyranoside, purified by affinity chromatography, and reconstituted into pre‐formed liposomes made from E. coli lipids. The properties of the reconstituted, purified enzyme were not significantly different from the membranous enzyme. These data demonstrate that cysteine‐less FOF1 is biochemically stable and has functionality similar to wild‐type.