title: Novel alkali-tolerant GH10 endo-β-1,4-xylanase with broad substrate specificity from Microbacterium trichothecenolyticum HY-17, a gut bacterium of the mole cricket Gryllotalpa orientalis.
abstract: The XylH gene (1,167-bp) encoding a novel hemicellulase (41,584 Da) was identified from the genome of Microbacterium trichothecenolyticum HY-17, a gastrointestinal bacterium of Gryllotalpa orientalis. The enzyme consisted of a single catalytic domain, which is 74% identical to that of an endo-β-1,4-xylanase (GH10) from Isoptericola variabilis 225. Unlike other endo-β- 1,4-xylanases from invertebrate-symbiotic bacteria, rXylH was an alkali-tolerant multifunctional enzyme possessing endo-β-1,4-xylanase activity together with β-1,3/β-1,4- glucanase activity, which exhibited its highest xylanolytic activity at pH 9.0 and 60°C, and was relatively stable within a broad pH range of 5.0-10.0. The susceptibilities of different xylosebased polysaccharides to the XylH were assessed to be as follows: oat spelts xylan > beechwood xylan > birchwood xylan > wheat arabinoxylan. rXylH was also able to readily cleave p-nitrophenyl (pNP) cellobioside and pNP-xylopyranoside, but did not hydrolyze other pNP-sugar derivatives, xylobiose, or hexose-based materials. Enzymatic hydrolysis of birchwood xylan resulted in the product composition of xylobiose (71.2%) and xylotriose (28.8%) as end products.
authors.affiliation: Industrial Bio-materials Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Republic of Korea.
authors.forename: Do Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Dong-Ha
authors.initials: DH
authors.lastname: Shin
authors.forename: Sora
authors.initials: S
authors.lastname: Jung
authors.forename: Hyangmi
authors.initials: H
authors.lastname: Kim
authors.forename: Jong Suk
authors.initials: JS
authors.lastname: Lee
authors.forename: Han-Young
authors.initials: HY
authors.lastname: Cho
authors.forename: Kyung Sook
authors.initials: KS
authors.lastname: Bae
authors.forename: Chang-Keun
authors.initials: CK
authors.lastname: Sung
authors.forename: Young Ha
authors.initials: YH
authors.lastname: Rhee
authors.forename: Kwang-Hee
authors.initials: KH
authors.lastname: Son
authors.forename: Ho-Yong
authors.initials: HY
authors.lastname: Park
mesh_terms: D000192:Actinomycetales / Q000145:classification / Q000201:enzymology* / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006135:Gryllidae / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D043364:Endo-1,4-beta Xylanases