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A novel enzymatic production system of optically pure β-hydroxy α-amino acids was developed. Two enzymes were used for the system: an N-succinyl L-amino acid β-hydroxylase (SadA) belonging to the iron(II)/α-ketoglutarate-dependent dioxygenase superfamily and an N-succinyl L-amino acid desuccinylase (LasA). The genes encoding the two enzymes are part of a gene set responsible for the biosynthesis of peptidyl compounds found in the Burkholderia ambifaria AMMD genome. SadA stereoselectively hydroxylated several N-succinyl aliphatic L-amino acids and produced N-succinyl β-hydroxy L-amino acids, such as N-succinyl- L-β-hydroxyvaline, N-succinyl- L-threonine, (2 S,3 R)- N-succinyl- L-β-hydroxyisoleucine, and N-succinyl- L- threo-β-hydroxyleucine. LasA catalyzed the desuccinylation of various N-succinyl- L-amino acids. Surprisingly, LasA is the first amide bond-forming enzyme belonging to the amidohydrolase superfamily, and has succinylation activity towards the amino group of L-leucine. By combining SadA and LasA in a preparative scale production using N-succinyl- L-leucine as substrate, 2.3 mmol of L- threo-β-hydroxyleucine were successfully produced with 93% conversion and over 99% of diastereomeric excess. Consequently, the new production system described in this study has advantages in optical purity and reaction efficiency for application in the mass production of several β-hydroxy α-amino acids. [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Makoto Hibi, Jun Ogawa et al., depicts Fe(II)/α ‐ ketoglutarate (αKG) ‐ dependent dioxygenases, which are hydroxylation biocatalysts catalyzing highly selective monooxygenation available to industrial applications. Recently, a great number of Fe(II)/αKG ‐ dependent dioxygenases with a variety of functions has been found in the genome database, and collected into a biocatalyst library. One of these enzymes, N ‐ succinyl L ‐ amino acid β ‐ hydroxylase, was applied to an enzymatic cascade system together with N ‐ succinyl L ‐ amino acid desuccinylase for the production of optically pure β ‐ hydroxy α ‐ amino acids. Details can be found in the full paper on pages 767 – 774 (M. Hibi, T. Kasahara, T. Kawashima, H. Yajima, S. Kozono, S. V. Smirnov, T. Kodera, M. Sugiyama, S. Shimizu, K. Yokozeki, and J. Ogawa, Adv. Synth. Catal. 2015, 357, 767 – 774; DOI: 10.1002/adsc.201400672). [ABSTRACT FROM AUTHOR]