An Engineered Old Yellow Enzyme that Enables Efficient Synthesis of (4R,6R)-Actinol in a One-Pot Reduction System
Horita, S., Kataoka, M., Kitamura, N., Nakagawa, T., Miyakawa, T., Ohtsuka, J., Nagata, K., Shimizu, S., Tanokura, M.(2015) Chembiochem 16: 440-445
- PubMed: 25639703 
- DOI: https://doi.org/10.1002/cbic.201402555
- Primary Citation of Related Structures:  
4TMB, 4TMC - PubMed Abstract: 
(4R,6R)-Actinol can be stereo-selectively synthesized from ketoisophorone by a two-step conversion using a mixture of two enzymes: Candida macedoniensis old yellow enzyme (CmOYE) and Corynebacterium aquaticum (6R)-levodione reductase. However, (4S)-phorenol, an intermediate, accumulates because of the limited substrate range of CmOYE. To address this issue, we solved crystal structures of CmOYE in the presence and absence of a substrate analogue p-HBA, and introduced point mutations into the substrate-recognition loop. The most effective mutant (P295G) showed two- and 12-fold higher catalytic activities toward ketoisophorone and (4S)-phorenol, respectively, than the wild-type, and improved the yield of the two-step conversion from 67.2 to 90.1%. Our results demonstrate that the substrate range of an enzyme can be changed by introducing mutation(s) into a substrate-recognition loop. This method can be applied to the development of other favorable OYEs with different substrate preferences.
Organizational Affiliation: 
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan).