title: Cloning and expression of a Clostridium thermocellum xylanase gene in Escherichia coli.
abstract: A Clostridium thermocellum xylanase gene, designated xynX, was cloned in Escherichia coli and was categorized a novel gene as a result of the comparison of restriction patterns of the C. thermocellum xylanase genes so far reported. The xynX gene encodes a xylanase having the molecular weight of 105 kilodaltons. A number of smaller truncated proteins with activities towards 4-methylumbelliferyl-beta-D-cellobioside and xylan were also produced. The enzyme hydrolyzed xylan to xylo-oligosaccharide, indicating typical activity of endo-beta-1,4-xylanase. This endoxylanase hydrolyzed carboxymethylcellulose without notable reduction of the viscosity as an exo-beta-1,4-glucanase, even though the enzyme exhibited very low levels of activity against other soluble and insoluble cellulosic substrates.
authors.affiliation: Bacterial Molecular Genetics Research Unit, Korea Research Institute of Bioscience & Biotechnology (KRIBB), Yusong, Taejon, Korea.
authors.forename: K H
authors.initials: KH
authors.lastname: Jung
authors.forename: K M
authors.initials: KM
authors.lastname: Lee
authors.forename: H
authors.initials: H
authors.lastname: Kim
authors.forename: K H
authors.initials: KH
authors.lastname: Yoon
authors.forename: S H
authors.initials: SH
authors.lastname: Park
authors.forename: M Y
authors.initials: MY
authors.lastname: Pack
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D002475:Cellobiose / Q000031:analogs & derivatives / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods; D003013:Clostridium / Q000201:enzymology / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D005798:Genes, Bacterial / Q000235:genetics*; D006868:Hydrolysis; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins; D015183:Restriction Mapping; D013379:Substrate Specificity; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D011993:Recombinant Fusion Proteins; D014990:Xylans; D002475:Cellobiose; C068475:4-methylumbelliferylcellobioside; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002266:Carboxymethylcellulose Sodium