title: Molecular cloning and characterization of a beta-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family.
abstract: Extensin is a glycoprotein that is rich in hydroxyprolines linked to β-L-arabinofuranosides. In this study, we cloned a hypBA2 gene that encodes a novel β-L-arabinobiosidase from Bifidobacterium longum JCM 1217. This enzyme does not have any sequence similarity with other glycoside hydrolase families but has 38-98% identity to hypothetical proteins in Bifidobacterium and Xanthomonas strains. The recombinant enzyme liberated L-arabinofuranose (Araf)-β1,2-Araf disaccharide from carrot extensin, potato lectin, and Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(3)-Hyp) but not Araf-α1,3-Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(4)-Hyp) or Araf-β1,2-Araf-β-Hyp (Ara(2)-Hyp), which indicated that it was specific for unmodified Ara(3)-Hyp substrate. The enzyme also transglycosylated 1-alkanols with retention of the anomeric configuration. This is the first report of an enzyme that hydrolyzes Hyp-linked β-L-arabinofuranosides, which defines a new family of glycoside hydrolases, glycoside hydrolase family 121.
authors.affiliation: Faculty of Agriculture, Kagoshima University, Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fujita
authors.forename: Shiho
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ono
authors.forename: Masahiro
authors.initials: M
authors.lastname: Wakao
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Suda
authors.forename: Kanefumi
authors.initials: K
authors.lastname: Kitahara
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Suganuma
mesh_terms: D000595:Amino Acid Sequence; D001089:Arabinose / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001644:Bifidobacterium / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D014974:Xanthomonas / Q000201:enzymology / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C431714:arabinofuranose; D001089:Arabinose; D006026:Glycoside Hydrolases