Structure of cytochrome P450 2B4 with an acetate ligand and an active site hydrogen bond network similar to oxyferrous P450cam

Superposition of the active site of acetate-bound P4502B4 and oxyferrous P450cam. Bond lengths between the heme iron, the sixth ligand, and the hydroxyl of the conserved threonine are shown. Note that different threonine rotamers form the hydrogen bonds to the acetate and oxygen. [Display omitted] •Crystal structure of cytochrome P450 2B4 in complex with acetate•Two water molecules insert in the I-helix of the cytochrome P450 2B4 mutant active site•In cytochrome P450 2B4 acetate binds to the heme and side chain of Thr302.•The acetate bound active site of ferric cytochrome P450 2B4 resembles that of the oxygen bound P450cam.