title: A new xylanase from thermoacidophilic Alicyclobacillus sp. A4 with broad-range pH activity and pH stability.
abstract: We have identified a highly pH-adaptable and stable xylanase (XynA4) from the thermoacidophilic Alicyclobacillus sp. A4, a strain that was isolated from a hot spring in Yunnan Province, China. The gene (xynA4) that encodes this xylanase was cloned, sequenced, and expressed in Escherichia coli. It encodes a 338-residue polypeptide with a calculated molecular mass of 42.5 kDa. The deduced amino acid sequence is most similar to (53% identity) an endo-1,4-beta-xylanase from Geobacillus stearothermophilus that belongs to family 10 of the glycoside hydrolases. Purified recombinant XynA4 exhibited maximum activity at 55 degrees C and pH 7.0, had broad pH adaptability (>40% activity at pH 3.8-9.4) and stability (retaining >80% activity after incubation at pH 2.6-12.0 for 1 h at 37 degrees C), and was highly thermostable (retaining >90% activity after incubation at 60 degrees C for 1 h at pH 7.0). These properties make XynA4 promising for application in the paper industry. This is the first report that describes cloning and expression of a xylanase gene from the genus Alicyclobacillus.
authors.affiliation: Feed Research Institute, Beijing, People's Republic of China.
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Bai
authors.forename: Jianshe
authors.initials: J
authors.lastname: Wang
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D056450:Alicyclobacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D014995:Xylosidases / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D014995:Xylosidases