Crystal structure of cytochrome P450 CYP105N1 from Streptomyces coelicolor, an oxidase in the coelibactin siderophore biosynthetic pathway

[Display omitted] ► The crystal structure of Streptomyces coelicolor CYP105N1 was determined at 2.9Å resolution. ► The CYP105N1 substrate binding pocket has a wide open conformation. ► Recombinant CYP105N1 successfully converted estradiol to estriol. The genome sequence of Streptomyces coelicolor contains 18 cytochrome P450 enzymes. The recombinant CYP105N1 protein has been expressed in Escherichia coli and purified, and we report the biochemical and structural characterization of CYP105N1 from S. coelicolor. The purified protein exhibited the typical CO-binding spectrum of P450 enzymes and type I binding spectra with estradiol and a coelibactin analog. The oxidation of estradiol by CYP105N1, supported by H2O2, produced estriol. The crystal structure of CYP105N1 was determined at 2.9Å resolution. An unexpected wide open binding pocket located above the heme group was identified, with a volume of approximately 4299Å3. These results suggest that the large open pocket to the active site may be a key feature for easy access of the peptidyl carrier protein-bound substrate to perform the hydroxylation reaction. A molecular docking model with coelibactin showed that the phenyl group of coelibactin is located