Oxygenation Cascade Analysis in Conversion of N-Octane Catalyzed By Cytochrome P450 CYP102A3 Mutants at P331 Site

To improve the hydroxylation efficiency of cytochrome P450 CYP102A3 to substrate n-octane, a previously reported triple mutant F88V/S188Q/A330V with altered regioselectivity was selected and site-saturation mutagenesis was performed at its P331 site which is adjacent to one of the active sites A330. Using whole-cell biotransformations to analyze the created mutants, four better mutants P331A, P331T, P331S and P331V were achieved and exhibited significantly improved conversion rate towards octane, which are 33%, 33%, 22% and 28%, respectively. Whereas the activity of P331R was greatly reduced and P331K gave almost zero conversion of n-octane. Besides the main product octanols, different octanones and 1,7-octanediol were also detected for some of the mutants. The above results demonstrated that the P331 site of CYP102A3 also plays an important role on the octane oxidation and CYP102A3 is a functionally flexible biocatalyst that can be optimised for a variety of industrial applications.