Elucidating the role of the proximal cysteine hydrogen-bonding network in ferric cytochrome P450cam and corresponding mutants using magnetic circular dichroism spectroscopy.

ABSTRACT: Although extensive research has been performed on various cytochrome P450s, especially Cyt P450cam, there is much to be learned about the mechanism of how its functional unit, a heme b ligated by an axial cysteine, is finely tuned for catalysis by its second coordination sphere. Here we study how the hydrogen-bonding network affects the proximal cysteine and the Fe-S(Cys) bond in ferric Cyt P450cam. This is accomplished using low-temperature magnetic circular dichroism (MCD) spectroscopy on wild-type (wt) Cyt P450cam and on the mutants Q360P (pure ferric high-spin at low temperature) and L358P where the "Cys pocket" has been altered (by removing amino acids involved in the hydrogen-bonding network), and Y96W (pure ferric low-spin). The MCD spectrum of Q360P reveals fourteen electronic tran

SUBMITTER: Galinato MG 

PROVIDER: S-EPMC3035745 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature