title: Semisynthesis of cytochrome c analogues. The effect of modifying the conserved residues 38 and 39.
abstract: We have used chemical and enzymic protein engineering techniques to create analogues of the semisynthetic two-fragment complex (1-37).(38-104) of mitochondrial cytochrome c. This complex, unlike the natural product of specific tryptic cleavage, (1-38).(39-104), from which it is prepared, quite closely resembles the parent protein in functional characteristics and is thus a suitable substrate for modifications designed to study structure-function relations. We have replaced the invariant Arg-38 and the conserved Lys-39 with a range of alternative amino acids and have studied the effects on the principal functional parameters. The hydrogen-bonding capacity of Arg-38 is crucial to the stabilization of the bottom omega-loop, while the positive charge of Lys-39 helps maintain the high redox potential by electrostatic effects at the haem iron.
authors.affiliation: Université de Genève, Département de Biochimie Médicale, Switzerland.
authors.forename: A E
authors.initials: AE
authors.lastname: Proudfoot
authors.forename: C J
authors.initials: CJ
authors.lastname: Wallace
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001120:Arginine; D003574:Cytochrome c Group / Q000138:chemical synthesis* / Q000378:metabolism; D008239:Lysine; D010084:Oxidation-Reduction; D013329:Structure-Activity Relationship
chemical_list: D000596:Amino Acids; D003574:Cytochrome c Group; D001120:Arginine; D008239:Lysine