title: XynX, a possible exo-xylanase of Aeromonas caviae ME-1 that produces exclusively xylobiose and xylotetraose from xylan.
abstract: A gene, xynX, encoding a novel xylanase, was cloned from Aeromonas caviae ME-1. This gene encoded an enzyme that was constituted of 334 amino acid residues (38,580 Da) and was similar in sequence to Family 10 (Family F) beta-1,4 endo-xylanases. XynX produced only xylobiose and xylotetraose from birch wood xylan, and xylotriose, xylopentaose, and higher oligosaccharides were not detected in the TLC analysis. We designated it as X2/X4-forming xylanase. This enzyme does not have transglycosylation activity. These data suggested that this enzyme is a possible exo-xylanase. According to homology modeling, the enzyme has a ring-shaped (alpha/beta)8 barrel (TIM barrel) structure, typical of Family 10 endo-xylanases, with the extraordinary feature of a longer bottom-loop structure.
authors.affiliation: Department of Biotechnology, Faculty of Agriculture, Gifu University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Usui
authors.forename: K
authors.initials: K
authors.lastname: Ibata
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Kawai
mesh_terms: D000333:Aeromonas / Q000201:enzymology / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D004187:Disaccharides / Q000096:biosynthesis*; D005798:Genes, Bacterial; D005815:Genetic Code; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000096:biosynthesis* / Q000378:metabolism*; D014995:Xylosidases / Q000235:genetics*
chemical_list: D004187:Disaccharides; D014990:Xylans; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; C004173:xylobiose