An Aminocaprolactam Racemase from Ochrobactrum anthropi with Promiscuous Amino Acid Ester Racemase Activity.
Frese, A., Barrass, S.V., Sutton, P.W., Adams, J.P., Grogan, G.(2018) Chembiochem
- PubMed: 29897155
- DOI: https://doi.org/10.1002/cbic.201800265
- Primary Citation of Related Structures:
6GIO - PubMed Abstract:
The kinetic resolution of amino acid esters (AAEs) is a useful synthetic strategy for the preparation of single-enantiomer amino acids. The development of an enzymatic dynamic kinetic resolution (DKR) process for AAEs, which would give a theoretical yield of 100 % of the enantiopure product, would require an amino acid ester racemase (AAER); however, no such enzyme has been described. We have identified low AAER activity of 15 U mg -1 in a homologue of a PLP-dependent α-amino ϵ-caprolactam racemase (ACLR) from Ochrobactrum anthropi. We have determined the structure of this enzyme, OaACLR, to a resolution of 1.87 Å and, by using structure-guided saturation mutagenesis, in combination with a colorimetric screen for AAER activity, we have identified a mutant, L293C, in which the promiscuous AAER activity of this enzyme towards l-phenylalanine methyl ester is improved 3.7-fold.
Organizational Affiliation:
York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.