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The binding interface between cytochrome b(sub)5 and cytochrome c is investigated to understand the molecular mechanism involved in the electron-transport reactions between the cytochromes. Data show that 51% of cytochrome b(sub)5 residues exhibit chemical shift changes and these residues are localized to the binding interface.

The effect of mutations on the structure and folding properties of rat and bovine apocytochrome b5 were determined by molecular dynamics simulations. Heme removal resulted in significant changes in the structure and dynamics of the apo form compared to the native holoprotein. There were wide deviations in the experimental results for the rat apoprotein. The behavior of the two hydrophobic cores did not agree with their expected behavior. Core 1 exhibited significant conformational changes while core 2 retained its native structure.

The cytochrome b5, involved in protein-protein interactions and electron-transfer reactions, undergoes a temporary structural deviation when simulated in water at a temperature of 298K and pH 6.9, before reverting back to its original crystalline conformation.simulation detects a A region of protein backbone that changed structure consists of acidic residues, suggesting electrostatic-based protein-protein recognition. This suggests that a low-energy mechanism for controlling recognition events ay be thermal motion.

A study conducted on the heme-containing protein, cytochrome b5, introduced mutations in the protein in an attempt to alter and thereby test cleft formation. Computer modeling and mutagenesis were used to design and produce two cytochrome b5 mutants, an S18D mutant and a disulfide mutant, that would restrict the cleft fluctuations. The effects of the mutations on equilibrium stability were also investigated experimentally. Results are discussed.

A study on the hemoprotein cytochrome b5 was conducted to test previous experimental results which had indicated that the molecule is highly dynamic in solution and has redox-state-dependent differences in mobility near the cleft region. Site-directed mutants aimed at perturbing cleft dynamics were constructed with a disulfide or salt bridge. Equilibrium denaturation investigations were performed while experimental methods and results were also discussed.