[Structure of the Micrococcus lysodeikticus respiratory chain using low concentrations of Triton X-100 and glutaric...

Using low (0.0025 -- 0.025%) concentrations of Triton X-100, the correlation between the decrease of NADN- and malate oxidase activities and NADH- and malate dehydrogenase release in large fragments of Micrococcus lysodeikticus membranes was established. This was accompanied by membrane suspension clearance and a decrease of microviscosity of the membrane lipid component. Using NADH-dehydrogenase, it was shown that the attachment of NADH-dehydrogenase to the membrane treated with glutaric aldehyde occurs in two steps, this being indicative of different environment of this enzyme in the membrane. The data obtained are discussed in terms of laterally heterogenous structure of the bacterial membrane with respect to the electron transport enzymes, in particular in favour of an existence of individual sites of the membrane containing dehydrogenases rather than other respiratory chain components.