Substrate Hunting for the Myxobacterial CYP260A1 Revealed New 1α‐Hydroxylated Products from C‐19 Steroids

Abstract Cytochromes P450 catalyze a variety of synthetically useful reactions. However, it is difficult to determine their physiological or artificial functions when a plethora of orphan P450 systems are present in a genome. CYP260A1 from Sorangium cellulosum So ce56 is a new member among the 21 available P450s in the strain. To identify putative substrates for CYP260A1 we used high‐throughput screening of a compound library (ca. 17 000 ligands). Structural analogues of the type I hits were searched for biotechnologically relevant compounds, and this led us to select C‐19 steroids as potential substrates. We identified efficient surrogate redox partners for CYP260A1, and an Escherichia coli ‐based whole‐cell biocatalyst system was developed to convert testosterone, androstenedione, and their derivatives methyltestosterone and 11‐oxoandrostenedione. A detailed 1 H and 13 C NMR characterization of the product(s) from C‐19 steroids revealed that CYP260A1 is the very first 1α‐steroid hydroxylase.