F 1-ATPase of Micrococcus lysodeikticus is not a glycoprotein

Abstract

It has been claimed (Andreu, J.M., Warth, R. and Muñoz, E. (1978) FEBS Lett. 86, 1–5) that the F 1-ATPase of Micrococcus lysodeikticus is a glycoprotein containing mannose and glucose as the principal sugars. Even after extensive purification of M. lysodeikticus F 1-ATPase by DEAE-Sephadex A25 chromatography, carbohydrate contents varying from 2.7 to 10.8% have been found. Concanavalin A-reactive components corresponding to the succinylated lipomannan have been detected and separated from the ATPase in purified F 1 preparations by immunoelectrophoresis (rocket and two-dimensional) through agarose gels containing concanavalin A. Passage of the purified F 1-ATPase through concanavalin A-Sepharose 4B columns removed the carbohydrate component(s) without loss of the specific activity of the ATPase. Mannose was the only sugar detectable by gas-liquid chromatography of the F 1-ATPase before Con A-Sepharose 4B chromatography and it was completely eliminated after chromatography. No qualitative or quantitative changes in the subunit (α, β, γ, δ and ϵ) profiles were detectable when the sodium dodecyl sulfate polyacrylamide gels were scanned by densitometry of F 1-ATPase before and after Con A-Sepharose 4B chromatography. We conclude that there is no evidence of carbohydrate covalently linked to this F 1-ATPase and that this membrane protein is not a glycoprotein. The presence of carbohydrate is attributable to contamination with lipomannan.