title: Putative endoglucanase PcGH5 from Phanerochaete chrysosporium is a β-xylosidase that cleaves xylans in synergistic action with endo-xylanase.
abstract: A predicted endoglucanase gene (PcGH5) was cloned from Phanerochaete chysosporium, and expressed in Pichia pastoris. Although PcGH5 showed similarity with the conserved domains of a cellulase superfamily GH5, a β-glucosidase/6-phospho-β-glucosidase/β-galactosidase superfamily, and an endoglucanase, recombinant PcGH5 exhibited a β-xylosidase activity, rather than endoglucanase activity. Therefore, the predicted gene was named as PcXyl5. Further characterization of recombinant PcXyl5 showed not only catalysis of the hydrolysis of xylo-oligomers to xylose, but also displayed transglycosylation activity using alcohol as a receptor. Optimum pH of rPcXyl5 was found to be 5.5, whereas optimum temperature was 50°C. rPcXyl5 increased reducing sugar release of birchwood xylan, beechwood xylan, and arabinoxylan by 6.4%, 13%, 15.8%, respectively, in synergistic action with endo-xylanase. Interestingly, the late addition of rPcXyl5 into reaction with endo-xylanase resulted in a larger increase of reducing sugar release from pretreated barley straw that addition at the start or by treatment with endo-xylanases alone. The increases observed were 6.3% and 13.8%, respectively, showing a great potential application for hemicellulose saccharification.
authors.affiliation: Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, Jeonbuk 570-752, Republic of Korea.
authors.forename: Nguyen Duc
authors.initials: ND
authors.lastname: Huy
authors.affiliation: Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, Jeonbuk 570-752, Republic of Korea.
authors.forename: Cu Le
authors.initials: CL
authors.lastname: Nguyen
authors.affiliation: Applied Microbiology Research Center, Bio-Materials Research Institute, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup, Jeonbuk 580-185, Republic of Korea.
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Seo
authors.affiliation: Department of Molecular Biology, College of Natural Sciences, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea.
authors.forename: Dae-Hyuk
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, Jeonbuk 570-752, Republic of Korea. Electronic address: smpark@chonbuk.ac.kr.
authors.forename: Seung-Moon
authors.initials: SM
authors.lastname: Park
mesh_terms: D055162:Biocatalysis; D002480:Cellulase / Q000737:chemistry / Q000378:metabolism; D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006031:Glycosylation; D001467:Hordeum / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D020075:Phanerochaete / Q000201:enzymology* / Q000235:genetics; D010843:Pichia / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013696:Temperature; D014990:Xylans / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism
chemical_list: D011134:Polysaccharides; D014990:Xylans; C007916:hemicellulose; C085118:arabinoxylan; D014994:Xylose; D014995:Xylosidases; D001616:beta-Galactosidase; C026579:exo-1,4-beta-D-xylosidase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases
keywords: Glycoside hydrolase family 5; Hemicellulose; Phanerochaete chrysosporium; Xylan; Xylosidase