title: Carnitine biosynthesis in Neurospora crassa: identification of a cDNA coding for epsilon-N-trimethyllysine hydroxylase and its functional expression in Saccharomyces cerevisiae.
abstract: The biosynthesis of L-carnitine in eukaryotic organisms was first elucidated in the ascomycete Neurospora crassa. The first step of the pathway is catalysed by epsilon-N-trimethyllysine hydroxylase (TMLH), which converts epsilon-N-trimethyllysine into beta-hydroxy-N-epsilon-trimethyllysine in a reaction dependent on alpha-ketoglutarate, Fe2+ and oxygen. Here we report on the cloning of the N. crassa TMLH cDNA and its functional expression in Saccharomyces cerevisiae. The TMLH cDNA contains an open reading frame of 1413 base pairs encoding a predicted polypeptide of 471 amino acids. The Michaelis-Menten constants of the heterologously expressed enzyme were determined for epsilon-N-trimethyllysine, alpha-ketoglutarate, Fe2+ and correspond to 0.33 mM, 133 microM and 46 microM, respectively.
authors.affiliation: Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, 7600, South Africa.
authors.forename: Jan H
authors.initials: JH
authors.lastname: Swiegers
authors.forename: Frédéric M
authors.initials: FM
authors.lastname: Vaz
authors.forename: Isak S
authors.initials: IS
authors.lastname: Pretorius
authors.forename: Ronald J A
authors.initials: RJ
authors.lastname: Wanders
authors.forename: Florian F
authors.initials: FF
authors.lastname: Bauer
mesh_terms: D000595:Amino Acid Sequence; D002331:Carnitine / Q000096:biosynthesis*; D003001:Cloning, Molecular; D016384:Consensus Sequence; D018076:DNA, Complementary; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D006899:Mixed Function Oxygenases; C436318:epsilon-N-trimethyllysine hydroxylase; D002331:Carnitine