title: A xylanase with high pH stability from Streptomyces sp. S27 and its carbohydrate-binding module with/without linker-region-truncated versions.
abstract: A xylanase gene, xynAS27, was isolated from a genomic library of Streptomyces sp. S27. The full-length gene consists of 1,434 bp and encodes 477 amino acids, including a putative signal peptide of 41 residues at its N-terminus. The mature xylanase comprises two functional domains, a family 10 glycoside hydrolase, and a family 13 carbohydrate-binding module (CBM), which were joined by a short Gly/Pro-rich linker region. The intact, the CBM-truncated and the CBM-linker-truncated versions of the mature proteins were expressed in Escherichia coli BL21 (DE3), purified to electrophoretic homogeneity and subsequently characterized. XynAS27 showed high pH stability over the pH range 2.2-12.0. XynAS27 may be a compelling tool for the food industry because it generates xylobiose (85% w/w) as the main product of xylan hydrolysis. The truncated versions showed less pH and thermal stability, and less affinity and hydrolytic activity to insoluble substrate than the intact one. These results indicate that the CBM of XynAS27 plays a key role in the hydrolysis of insoluble substrate, and the CBM and linker region are also important for the enzyme stability, and the linker region contributes more.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing 100081, People's Republic of China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Yaru
authors.initials: Y
authors.lastname: Wang
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Bai
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhou
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004187:Disaccharides / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D013696:Temperature; D014990:Xylans / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D004187:Disaccharides; D021382:Protein Sorting Signals; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D014990:Xylans; C055213:saccharide-binding proteins; D006026:Glycoside Hydrolases; D043364:Endo-1,4-beta Xylanases; C004173:xylobiose