title: Biosynthesis of 4-methylproline in cyanobacteria: cloning of nosE and nosF genes and biochemical characterization of the encoded dehydrogenase and reductase activities.
abstract: The biosynthesis of the unusual amino acid 4-methylproline in the Nostoc genus of cyanobacteria was investigated on the genetic and enzymatic level. Two genes involved in the biosynthesis were cloned and the corresponding enzymes, a zinc-dependent long-chain dehydrogenase and a Delta(1)-pyrroline-5-carboxylic acid (P5C) reductase homologue, were overexpressed in Escherichia coli and biochemically characterized. Putative substrates were synthesized to test enzyme substrate specificities, and deuterium labeling studies were carried out to reveal the stereospecificities of the enzymatic reactions with respect to the substrates as well as to the coenzymes.
authors.affiliation: Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Luesch
authors.forename: Dietmar
authors.initials: D
authors.lastname: Hoffmann
authors.forename: Joan M
authors.initials: JM
authors.lastname: Hevel
authors.forename: Julia E
authors.initials: JE
authors.lastname: Becker
authors.forename: Trimurtulu
authors.initials: T
authors.lastname: Golakoti
authors.forename: Richard E
authors.initials: RE
authors.lastname: Moore
mesh_terms: D002384:Catalysis; D000458:Cyanobacteria / Q000201:enzymology* / Q000235:genetics*; D004926:Escherichia coli; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009243:NAD / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D011392:Proline / Q000031:analogs & derivatives / Q000096:biosynthesis*; D011762:Pyrroline Carboxylate Reductases / Q000235:genetics / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase
chemical_list: D009243:NAD; D011392:Proline; D011762:Pyrroline Carboxylate Reductases; D000097502:delta-1-Pyrroline-5-Carboxylate Reductase; C474411:4-methylproline