title: A novel cold-active xylanase gene from the environmental DNA of goat rumen contents: direct cloning, expression and enzyme characterization.
abstract: A xylanase-coding gene, xynGR40, was cloned directly from the environmental DNA of goat rumen contents and expressed in Escherichia coli BL21 (DE3). The 1446-bp full-length gene encodes a 481-residue polypeptide (XynGR40) containing a catalytic domain belonging to glycosyl hydrolase (GH) family 10. Phylogenetic analysis indicated that XynGR40 was closely related with microbial xylanases of gastrointestinal source. Purified recombinant XynGR40 exhibited high activity at low temperatures, and remained active (∼10% of the activity) even at 0°C. The optimal temperature of XynGR40 was 30°C, much lower than other xylanases from rumen. Compared with mesophilic and thermophilic counterparts, XynGR40 had fewer hydrogen bonds and salt bridges, and lengthened loops in the catalytic domain. The enzyme also had relatively better stability at mesophilic temperatures and a higher catalytic efficiency than other known GH 10 cold active xylanases. These properties suggest that XynGR40 is a novel cold active xylanase and has great potential for basic research and industrial applications.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Guozeng
authors.initials: G
authors.lastname: Wang
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Yaru
authors.initials: Y
authors.lastname: Wang
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Bai
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics* / Q000302:isolation & purification*; D043364:Endo-1,4-beta Xylanases / Q000502:physiology*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006041:Goats; D008297:Male; D008969:Molecular Sequence Data; D012417:Rumen / Q000382:microbiology*; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D043364:Endo-1,4-beta Xylanases