Premium
A hypothetical complex between crystalline flavocytochrome b 2 and Cytochrome c
Author(s) -
Tegoni Mariella,
White Scott A.,
Roussel Alain,
Mathews F. Scott,
Cambillau Christian
Publication year - 1993
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340160409
Subject(s) - cytochrome c , crystallography , tetramer , cytochrome , chemistry , electron transfer , heme , protein subunit , molecule , hemeprotein , stereochemistry , mitochondrion , biochemistry , photochemistry , enzyme , organic chemistry , gene
Flavocytochrome b 2 and cytochrome c are physiological electron transfer partners in yeast mitochondria. The formation of a stable complex between them has been demonstrated both in solution and in the crystalline state. On the basis of the three‐dimensional structures, using molecular modeling and energy minimization, we have generated a hypothetical model for the interaction of these redox partners in the crystal lattice. General criteria such as good charge and surface complementarity, plausible orientation, and separation distance of the prosthetic groups, as well as more specific criteria such as the stoichiometry determined in the crystal, and the involvement of both domains and of more than one subunit of flavocytochrome b 2 led us to discriminate between several possible interaction sites. In the hypothetical model we present, four cytochrome c molecules interact with a tetramer of flavocytochrome b 2 . The b 2 and c hemes are coplanar, with an edge‐to‐edge distance of 14 Å. the contact surface area is ca. 800 Å 2 . Several electrostatic interactions involving the flavin and the heme domains of flavocytochrome b 2 stabilize the binding of cytochrome c . © 1993 Wiley‐Liss, Inc.