title: Improving the catalytic performance of a GH11 xylanase by rational protein engineering.
abstract: XynCDBFV from Neocallimastix patriciarum is among the most effective xylanases and holds great potentials in a wide variety of industrial applications. In the present study, several active site residues were modified referring to the instrumental information of the complex structure of XynCDBFV and xylooligosaccharides. Among the 12 single active site mutants, W125F and F163W show increased activity comparing to the wild-type protein. The double mutant W125F/F163W was then generated which displayed nearly 20 % increase in the enzyme activity. Although W125F/F163W showed 5 °C reduction in the optimal temperature, it still preserves similar thermostability and is more active than the wild-type enzyme at temperatures lower than 60 °C. These properties make the double mutant a suitable candidate for commercial applications that involve lower operating temperatures. Furthermore, we investigated the effect of N-glycosylation on the thermostability of XynCDBFV when expressed in the yeast strain Pichia pastoris for industrial use. Two potential glycosylation sites (Asn-37 and Asn-88) were examined, and their roles in enzyme performance were validated. We found that the N-glycosylations of XynCDBFV are related to both catalytic activity and heat stability, with Asn-37 motif playing a dominant role. Collectively, the enzymatic properties of XynCDBFV were improved by molecular engineering, and the influences of N-glycosylations on the enzyme have been clearly elucidated herein.
authors.affiliation: Genozyme Biotechnology Inc., Taipei, 106, Taiwan.|AsiaPac Biotechnology Co., Ltd., Dongguan, 523808, China.
authors.forename: Ya-Shan
authors.initials: YS
authors.lastname: Cheng
authors.affiliation: Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Genozyme Biotechnology Inc., Taipei, 106, Taiwan.|AsiaPac Biotechnology Co., Ltd., Dongguan, 523808, China.
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Huang
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Tzu-Ping
authors.initials: TP
authors.lastname: Ko
authors.affiliation: Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. guo_rt@tib.cas.cn.|, 32 XiQiDao, Tianjin Airport Economic Park, Tianjin, 300308, China. guo_rt@tib.cas.cn.
authors.forename: Rey-Ting
authors.initials: RT
authors.lastname: Guo
mesh_terms: D055162:Biocatalysis; D020134:Catalytic Domain / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004795:Enzyme Stability / Q000235:genetics; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D007218:Industrial Microbiology / Q000379:methods; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010843:Pichia / Q000201:enzymology* / Q000235:genetics*; D015202:Protein Engineering / Q000379:methods*; D017434:Protein Structure, Tertiary; D013696:Temperature
chemical_list: D006026:Glycoside Hydrolases; D043364:Endo-1,4-beta Xylanases
keywords: Glycoside hydrolase; Glycosylation; Mutagenesis; Structure-based design; Thermostability