An Aminocaprolactam Racemase from Ochrobactrum anthropi with Promiscuous Amino Acid Ester Racemase Activity

作者：Frese Amina; Barrass Sarah V; Sutton Peter W; Adams Joe P; Grogan Gideon^*

来源：ChemBioChem, 2018, 19(16): 1711-1715.

DOI：10.1002/cbic.201800265

• amino acid amides
• amino acid esters
• amino acids
• biocatalysis
• pyridoxal phosphate
• racemases

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 15Umg(-1) in a homologue of a PLP-dependent -amino E-caprolactam racemase (ACLR) from Ochrobactrum anthropi. We have determined the structure of this enzyme, OaACLR, to a resolution of 1.87 angstrom 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.

• 出版日期2018-8-16