title: Cloning and characterization of an antifungal class III chitinase from suspension-cultured bamboo ( Bambusa oldhamii ) cells.
abstract: A class III chitinase cDNA (BoChi3-1) was cloned using a cDNA library from suspension-cultured bamboo ( Bambusa oldhamii ) cells and then transformed into yeast ( Pichia pastoris X-33) for expression. Two recombinant chitinases with molecular masses of 28.3 and 35.7 kDa, respectively, were purified from the yeast's culture broth to electrophoretic homogeneity using sequential ammonium sulfate fractionation, Phenyl-Sepharose hydrophobic interaction chromatography, and Con A-Sepharose chromatography steps. N-Terminal sequencing and immunoblotting revealed that both recombinant chitinases were encoded by BoChi3-1, whereas SDS-PAGE and glycoprotein staining showed that the 35.7 kDa isoform (35.7 kDa BoCHI3-1) was glycosylated and the 28.3 kDa isoform (28.3 kDa BoCHI3-1) was not. For hydrolysis of ethylene glycol chitin (EGC), the optimal pH values were 3 and 4 for 35.7 and 28.3 kDa BoCHI3-1, respectively; the optimal temperatures were 80 and 70 degrees C, and the K(m) values were 1.35 and 0.65 mg/mL. The purified 35.7 kDa BoCHI3-1 hydrolyzed EGC more efficiently than the 28.3 kDa isoform, as compared with their specific activity and activation energy. Both recombinant BoCHI3-1 isoforms showed antifungal activity against Scolecobasidium longiphorum and displayed remarkable thermal (up to 70 degrees C) and storage (up to a year at 4 degrees C) stabilities.
authors.affiliation: Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Chao-Jen
authors.initials: CJ
authors.lastname: Kuo
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Liao
authors.forename: Ji-Han
authors.initials: JH
authors.lastname: Yang
authors.forename: Li-Chun
authors.initials: LC
authors.lastname: Huang
authors.forename: Chen-Tien
authors.initials: CT
authors.lastname: Chang
authors.forename: Hsien-Yi
authors.initials: HY
authors.lastname: Sung
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D031723:Bambusa / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D002478:Cells, Cultured; D002688:Chitinases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D000935:Antifungal Agents; D010940:Plant Proteins; D002688:Chitinases; C110892:chitinase, class III