1H-n.m.r. investigation of the interaction between cytochrome c and cytochrome b5.
The interaction between eukaryotic cytochrome c and the tryptic fragment of bovine liver microsomal cytochrome b5 was studied by 1H-n.m.r. spectroscopy, and a procedure was developed that may be generally applicable to the study of macromolecular interactions by n.m.r. At pH6.3 (27 degrees C, I approx. 0.04) the two ferricytochromes were found to form a 1:1 complex with an association constant of approx. 10(3) M -1. The protein--protein-interaction region was found to encompass the region of the surface of horse cytochrome c that includes Ile-81, Phe-82, Ala-83 and Ile-85, and Lys-13 and Lys-72 of horse cytochrome c were suggested to be involved in two important intermolecular interactions. Me3Lys-72 of Candida krusei cytochrome c was shown to be involved in the interaction.
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002857:Chromium; D003573:Cytochrome b Group / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism*; D015786:Cytochromes b5; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008862:Microsomes, Liver / Q000201:enzymology; D008958:Models, Molecular; D010070:Oxalates; D019815:Oxalic Acid; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding
D003573:Cytochrome b Group; D003574:Cytochrome c Group; D046911:Macromolecular Substances; D010070:Oxalates; D010446:Peptide Fragments; D002857:Chromium; D015786:Cytochromes b5; D019815:Oxalic Acid