Characterization of plasma membrane respiratory chain and ATPase in the actinomycete Nonomuraea sp. ATCC 39727

We have characterized the respiratory system of the aerobic actinomycete Nonomuraea sp. ATCC 39727. The plasma membrane of the microorganism is shown to contain a protonmotive respiratory chain and HI-ATPase. The respiratory chain is made up of a rotenone-sensitive NADH-quinone oxidoreductase, a four subunits aa(3)-type cytochrome c oxidase and a be, complex. The H+-ATPase is characterized as an F0F1-type on the basis of its sensitivity to specific inhibitors; the enzyme is also inhibited by mM concentrations of Ca2+. The activity of the respiratory chain increases during the exponential growth phase, but is depressed in the stationary phase. The H+-ATPase activity reaches, as the respiratory chain, a maximal activity at the end of the exponential growth phase and then remains constant in the stationary phase. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.