title: Three-dimensional structure of an alkaline xylanase Xyn11A-LC from alkalophilic Bacillus sp. SN5 and improvement of its thermal performance by introducing arginines substitutions.
abstract: The alkaline xylanase Xyn11A-LC from the alkalophilic Bacillus sp. SN5 was expressed in E. coli, purified and crystallized. The crystal structure was determined at a resolution of 1.49 Å. Xyn11A-LC has the β-jelly roll structure typical of family 11 xylanases. To improve its thermostability and thermophilicity, a mutant SB3 was constructed by introducing three arginines on the different sides of the protein surface. SB3 increased the optimum temperature by 5 °C. The wild type and SB3 had the half-lives of 22 and 68 min at 65 °C at pH 8.0 (Tris/HCl buffer), respectively. CD spectroscopy revealed that the melting temperature (T m) of the wild type and SB3 were 55.3 and 66.9 °C, respectively. These results showed that the introduction of arginines enhance the thermophilicity and thermostability of Xyn11A-LC.
authors.affiliation: National Engineering Lab for Industrial Enzymes, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China, bwqp450@163.com.
authors.forename: Wenqin
authors.initials: W
authors.lastname: Bai
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Xue
authors.forename: Chun-Hsiang
authors.initials: CH
authors.lastname: Huang
authors.forename: Rey-Ting
authors.initials: RT
authors.lastname: Guo
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D019943:Amino Acid Substitution; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013057:Spectrum Analysis; D013696:Temperature; D044366:Transition Temperature; D014995:Xylosidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D014995:Xylosidases