title: Purification and characterization of a novel chitinase gene from Paecilomyces thermophila expressed in Escherichia coli.
abstract: A novel chitinase gene (PtChiA) from the thermophilic fungus Paecilomyces thermophila was cloned and expressed in Escherichia coli as an intracellular soluble protein. The gene sequence alignment indicates that PtChiA belongs to glycoside hydrolase (GH) family 18 and has an open reading frame comprising of 1473 bp nucleotide sequences with five introns. PtChiA encodes 400 amino acids without any predicted signal peptide. PtChiA was purified by Ni-IDA chromatography. It displayed an acidic optimum pH of 4.5 and broad pH stability (pH 4.0-10.5). The enzyme exhibited an optimal temperature of 50°C and was stable up to 40°C. PtChiA was strongly inhibited by anionic detergent SDS, and also by metal ions Hg(2+) and Mn(2+). It did not exhibit any antifungal activity against pathogenic fungi. It has the ability to hydrolyze colloidal chitin into chito-oligomers suggesting its use in conversion of chitin waste into chito-oligosaccharides.
authors: Department of Biotechnology, College of Food Science and Nutritional Engineering, PO Box 294, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing 100083, China.
authors: Narasimha Kumar
authors: NK
authors: Kopparapu
authors: Peng
authors: P
authors: Zhou
authors: Shuping
authors: S
authors: Zhang
authors: Qiaojuan
authors: Q
authors: Yan
authors: Zhuqing
authors: Z
authors: Liu
authors: Zhengqiang
authors: Z
authors: Jiang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000494:pharmacology; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics*; D005658:Fungi / Q000187:drug effects; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010143:Paecilomyces / Q000201:enzymology* / Q000235:genetics*
chemical_list: D002686:Chitin; D002688:Chitinases