A novel, alkali-tolerant thermostable xylanase from Saccharomonospora viridis: direct gene cloning, expression and enzyme characterization.
A xylanase gene, designated Svixyn10A, was cloned from actinomycetes Saccharomonospora viridis and the gene product was characterized. Gene Svixyn10A contains 1,374 bp and encodes a polypeptide of 457 amino acids composed of a glycoside hydrolase family 10 catalytic domain with a putative signal peptide, a short Gly-rich linker and a family 2 carbohydrate-binding module (CBM). The deduced amino acid sequence of SviXyn10A shared the highest identity (57 %) with a hypothetical xylanase from Streptomyces lividans TK24 (ZP_05528201). A recombinant His-tagged xylanase, SviXyn10A was expressed in Escherichia coli BL21 and purified. The optimum pH and temperature for SviXyn10A is 8.0 and 60 °C. Compared with thermophilic and mesophilic counterparts, SviXyn10A was more active at high temperatures, retaining >63 % of its maximum activity at 65-70 °C and ~40 % even at 80 °C. It had broad pH adaptability (>35 % activity at pH 5.0-11.0) and alkali-tolerance (>70 % activity after incubation at pH 8.0-11.0 for 1 h at 37 °C), and was highly thermostable (>75 % activity after incubation at 70 °C for 3 h at pH 8.0). It may be the first alkali-tolerant thermostable xylanase reported from Saccharomonospora. These favorable properties make SviXyn10A a good candidate for application in pulp and paper industries.
College of Biological Sciences and Biotechnology, Beijing Forestry University, 35 QingHua East Road, Beijing, 100083, People's Republic of China.
Ziyuan
Z
Wang
Yi
Y
Jin
Huijun
H
Wu
Zhaofeng
Z
Tian
Yuying
Y
Wu
Xiangming
X
Xie
D000192:Actinomycetales / Q000145:classification / Q000201:enzymology* / Q000235:genetics*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000235:genetics* / Q000378:metabolism*; D004795:Enzyme Stability; D015870:Gene Expression; D005798:Genes, Bacterial; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D043364:Endo-1,4-beta Xylanases