title: Stereochemistry and mechanism of a microbial phenylalanine aminomutase.
abstract: The stereochemistry of a phenylalanine aminomutase (PAM) on the andrimid biosynthetic pathway in Pantoea agglomerans (Pa) is reported. PaPAM is a member of the 4-methylidene-1H-imidazol-5(4H)-one (MIO)-dependent family of catalysts and isomerizes (2S)-α-phenylalanine to (3S)-β-phenylalanine, which is the enantiomer of the product made by the mechanistically similar aminomutase TcPAM from Taxus plants. The NH(2) and pro-(3S) hydrogen groups at C(α) and C(β), respectively, of the substrate are removed and interchanged completely intramolecularly with inversion of configuration at the migration centers to form β-phenylalanine. This is a contrast to the retention of configuration mechanism followed by TcPAM.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Nishanka Dilini
authors.initials: ND
authors.lastname: Ratnayake
authors.forename: Udayanga
authors.initials: U
authors.lastname: Wanninayake
authors.forename: James H
authors.initials: JH
authors.lastname: Geiger
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Walker
mesh_terms: D002384:Catalysis; D015394:Molecular Structure; D020636:Pantoea / Q000201:enzymology*; D010649:Phenylalanine / Q000737:chemistry*; D010650:Phenylalanine Ammonia-Lyase / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D010649:Phenylalanine; D010650:Phenylalanine Ammonia-Lyase