title: A novel family of bacterial dioxygenases that catalyse the hydroxylation of free L-amino acids.
abstract: L-isoleucine-4-hydroxylase (IDO) is a recently discovered member of the Pfam family PF10014 (the former DUF 2257 family) of uncharacterized conserved bacterial proteins. To uncover the range of biochemical activities carried out by PF10014 members, eight in silico-selected IDO homologues belonging to the PF10014 were cloned and expressed in Escherichia coli. L-methionine, L-leucine, L-isoleucine and L-threonine were found to be catalysed by the investigated enzymes, producing L-methionine sulfoxide, 4-hydroxyleucine, 4-hydroxyisoleucine and 4-hydroxythreonine, respectively. An investigation of enzyme kinetics suggested the existence of a novel subfamily of bacterial dioxygenases within the PF10014 family for which free L-amino acids could be accepted as in vivo substrates. A hypothesis regarding the physiological significance of hydroxylated l-amino acids is also discussed.
authors.affiliation: Ajinomoto-Genetika Research Institute, Moscow, Russia. servasmi@mail.ru
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Smirnov
authors.forename: Pavel M
authors.initials: PM
authors.lastname: Sokolov
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kodera
authors.forename: Masakazu
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Hibi
authors.forename: Sakayu
authors.initials: S
authors.lastname: Shimizu
authors.forename: Kenzo
authors.initials: K
authors.lastname: Yokozeki
authors.forename: Jun
authors.initials: J
authors.lastname: Ogawa
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D049308:Dioxygenases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D006900:Hydroxylation; D007532:Isoleucine / Q000378:metabolism; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008715:Methionine / Q000378:metabolism; D013379:Substrate Specificity; D013912:Threonine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D007532:Isoleucine; D013912:Threonine; D008715:Methionine; D049308:Dioxygenases; D007930:Leucine