In paramagnetic compounds, coupling of the electron magnetic moment with the nuclear magnetic moment gives rise to the hyperfine shift (HFS) contribution to the nuclear magnetic resonance chemical shift. By measuring the HFS for several nuclei in a paramagnetic system, it is possible to generate a map of the unpaired electron spin density. For S = � Fe(III) heme, we have used this information plus density functional theory calculations to measure the electronic changes associated with out-of-plane deformations of the heme cofactor in cytochrome (cyt) c. We will discuss how these electronic changes are induced by the protein environment and how they tune the electron transfer properties of the cofactor. We will also discuss an application of our method to a variant of human cyt c with enhanced proapoptotic activity discovered in a family with thrombocytopenia and a multi-heme cyt c from a bacterium used for industrial recovery of metals.

Electronic changes in cytochromes <i>c</i> with functional consequences

240th National Meeting (2010)

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Electronic changes in cytochromes c with functional consequences