Structure and Function of the Cytochrome P450 Monooxygenase Cinnamate 4-hydroxylase from <i>Sorghum bicolor</i>
Bixia Zhang, K.M. Lewis, Alejandra Abril, Dmitri R. Davydov, Wilfred Vermerris, Scott E. Sattler, ChulHee Kang
Abstract
Here we report the 1.7 Å resolution crystal structure of CYP73A33. The obtained structural information, along with the results of the steady-state kinetic analysis and the absorption spectroscopy titration, displays a high degree of similarity of the structural and functional features of C4H to those of other P450 proteins. Our data also suggest the presence of a putative allosteric substrate-binding site in a hydrophobic pocket on the enzyme surface. In addition, comparing the newly resolved structure with those of well-investigated cytochromes P450 from mammals and bacteria enabled us to identify those residues of critical functional importance and revealed a unique sequence signature that is potentially responsible for substrate specificity and catalytic selectivity of C4H.