Involvement of ATP synthase residues αArg-376, βArg-182, and βLys-155 in Pi binding

alphaArg-376, betaLys-155, and betaArg-182 are catalytically important ATP synthase residues that were proposed to be involved in substrate Pi binding and subsequent steps of ATP synthesis [Senior, A.E., Nadanaciva, S. and Weber, J. (2002) Biochim. Biophys. Acta 1553, 188-211]. Here, it was shown using purified Escherichia coli F-1-ATPase that whereas Pi protected wild-type from reaction with 7-chloro-4-nitrobenzo-2oxa-1,3-diazole, mutations betaK155Q, betaR182Q, betaR182K, and alphaR376Q abolished protection. Therefore, in ATP synthesis initial binding of substrate Pi in open catalytic site betaE is supported by each of these three residues. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.