Enzymatic synthesis of enantiopure alpha- and beta-amino acids by phenylalanine aminomutase-catalysed amination of cinnamic acid derivatives.
The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of alpha-phenylalanine to beta-phenylalanine, an important step in the biosynthesis of the N-benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important beta-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic alpha- and beta-amino acids in excellent enantiomeric excess (ee >99 %). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent.
Wu
Bian
B
Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Szymanski
Wiktor
W
Wietzes
Piet
P
de Wildeman
Stefaan
S
Poelarends
Gerrit J
GJ
Feringa
Ben L
BL
Janssen
Dick B
DB
D000586:Amination; D000641:Ammonia / Q000378:metabolism; D055162:Biocatalysis; D002934:Cinnamates / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D019751:Intramolecular Transferases / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010649:Phenylalanine / Q000737:chemistry* / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D020946:Taxus / Q000201:enzymology*
D002934:Cinnamates; D007093:Imidazoles; C029010:cinnamic acid; D010649:Phenylalanine; D000641:Ammonia; C029899:imidazole; D019751:Intramolecular Transferases