1. Improving Hydrolysis Characteristics of Xylanases by Site-Directed Mutagenesis in Binding-Site Subsites from Streptomyces L10608
- Author
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Qin Li, Baoguo Sun, Gao Siyu, Ke Xiong, Xiuting Li, and Xiong Suyue
- Subjects
0301 basic medicine ,Oligosaccharides ,Glucuronates ,Xylose ,Streptomyces ,Article ,Catalysis ,Substrate Specificity ,Inorganic Chemistry ,lcsh:Chemistry ,03 medical and health sciences ,Hydrolysis ,chemistry.chemical_compound ,Bacterial Proteins ,Hydrolase ,Xylooligosaccharide ,Physical and Theoretical Chemistry ,Binding site ,Site-directed mutagenesis ,Molecular Biology ,lcsh:QH301-705.5 ,Spectroscopy ,Binding Sites ,biology ,Chemistry ,binding site ,Organic Chemistry ,GH10/11-xylanase ,General Medicine ,biology.organism_classification ,Computer Science Applications ,Xylosidases ,030104 developmental biology ,Amino Acid Substitution ,Biochemistry ,lcsh:Biology (General) ,lcsh:QD1-999 ,Xylanase ,Xylans ,Protein Binding - Abstract
The preparation of oligosaccharides via xylan hydrolysis is an effective way to add value to hemicellulosic material of agricultural waste. The bacterial strain Streptomyces L10608, isolated from soil, contains genes encoding xylanases of glucoside hydrolase family 10/11 (GH10/11), and these have been cloned to catalyze the production of xylooligosaccharide (XOS). To improve the XOS proportion of hydrolysates produced by xylanase, four amino acid residues were substituted by site-directed mutagenesis, and the mutant genes were overexpressed in Escherichia coli. Mutations replaced the codons encoding Asn214 (+2) and Asn86 (−2) by Ala and removed the Ricin B-lectin domain in GH10-xyn, and mutants Y115A (−2) and Y123A (−2) were produced for GH11-xyn. Interestingly, GH10-N86Q had significantly increased hydrolysis of XOS and almost eliminated xylose (X1) to
- Published
- 2018