Electron tunneling rates through the a-helices of cytochrome b562, in which the heme is bound solely by iron-ligand interactions, were previously determined by group of HB Gray in Caltech.  They have modified the protein to a c-type cytochrome (cyt c-b562) by covalently linking the porphyrin to the protein backbone.  In this modified protein, the heme is coordinated more rigidly to the protein than in the wild type protein.  We investigate the effects of these changes to the protein structure on the electron transfer rates in a series of Ru-modified mutants.We developed a computational methodology that uses an ab initio Hartree-Fock approach together with molecular dynamics simulations to computing electronic coupling interactions. This methodology is able to predict electronic coupling and electron transfer rates quantitatively. We compare our theoretical results with results from experiment. We use developed methodology to elucidate details how protein mediates electron transfer and identify origin of changes observed in experiment.

Ab initio approach to computing electronic coupling to develop an understanding of electron transfer  in ruthenium-modified cytochrome c-b562

243rd National Meeting (2012)

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