title: [Hydrophobic interaction between beta-sheet B1 and B2 in xylanase XYNB influencing the enzyme thermostability].
abstract: A homology modeling of xylanase XYNB from Streptomyces olivaceoviridis A1 was made by Swiss-Model. The hydrophobic Interaction between beta-sheet B1 and B2 in the tertiary structure model of XYNB was compared with other thermophilic xylanase. A T11Y mutation was introduced in XYNB by site-dirrected mutagenesis to improve the thermostability of the enzyme. The XYNB and mutant xylanase (XYNB') expressed in Pichia pastoris were purified and their enzymatic properties were determined. The result revealed that the thermostability of XYNB' was obviously higher than that of XYNB. The optimal temperature of XYNB' for its activity was 60 degrees C, similar to XYNB. But, compare to XYNB, the optimal pH value, the Km value and the specific activity of XYNB' had also been changed. The research results suggested that the aromatic interaction between beta-sheet B1 and B2 in xylanase should increase enzyme thermostability. The mutant xylanase XYNB' is a good material for further research in the relationship between structure and function of xylanase.
authors.affiliation: Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Hao-Meng
authors.initials: HM
authors.lastname: Yang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
authors.forename: Hui-Ying
authors.initials: HY
authors.lastname: Luo
authors.forename: Wang-Zhao
authors.initials: WZ
authors.lastname: Zhang
authors.forename: Ya-Ru
authors.initials: YR
authors.lastname: Wang
authors.forename: Tie-Zheng
authors.initials: TZ
authors.lastname: Yuan
authors.forename: Ying-Guo
authors.initials: YG
authors.lastname: Bai
authors.forename: Ning-Feng
authors.initials: NF
authors.lastname: Wu
authors.forename: Yun-Liu
authors.initials: YL
authors.lastname: Fan
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics; D004795:Enzyme Stability; D006358:Hot Temperature; D057927:Hydrophobic and Hydrophilic Interactions; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D050505:Mutant Proteins; D011994:Recombinant Proteins; D001617:beta-Glucosidase; D043364:Endo-1,4-beta Xylanases; C090001:XynB xylanase