[Molecular organization of cholesterol-hydroxylating cytochrome P-450 from adrenal cortex mitochondria. Chemical modification with bifunctional reagents in the study of oligomeric forms].

The molecular organization of adrenocortical cytochrome P-450scc has been investigated using chemical modification with bifunctional imidates. The oligomeric organization of cytochrome P-450scc in solution has been shown. The application of dimethyl-3,3'-dithiobispropioimidate and subsequent cleavage of the modified products by reducing agents revealed the presence of two types of intramolecular cross-links: "short" at the distance of 3,0 A between the amino groups of lysine residues and "long" ones at a distance of 11,9 A. The analysis of the products, obtained by limited proteolysis of the oligomeric forms of the cross-linked cytochrome P-450, by two-dimensional electrophoresis has shown that the cross-links are formed between the functional domain (fragment F1) and domain responsible for the interaction with the phospholipid membrane (fragment F2). A model for cytochrome P-450scc molecular organization has been suggested on the basis of the obtained results.