Cloning of the Bacillus thuringiensis serovar sotto chitinase (Schi) gene and characterization of its protein

• Main Authors: Wan-Fang Zhong, Ji-Chao Fang, Ping-Zhong Cai, Wen-Zhao Yan, Jie Wu, Hui-Fang Guo
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Genética 2005-12-01
• Series: Genetics and Molecular Biology
• Subjects: Bacillus thuringiensis serovar sotto; chitinase; touchdown PCR; gene cloning; characterization analysis
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000500026

Chitinase plays a positive role in the pathogenicity of Bacillus thuringiensis to insect pests. We used touchdown PCR to clone the chitinase (Schi) gene from Bacillus thuringiensis serovar sotto (Bt sotto) chromosomal DNA. Our DNA sequencing analysis revealed that the Bt sotto Schi gene consists of an open reading frame (ORF) of 2067 nucleotides with codes for the chitinase precursor. We also found that the putative promoter consensus sequences (the -35 and -10 regions) of the Bt soto Schi gene are identical to those of the chiA71 gene from Bt Pakistani, the chiA74 gene from Bt kenyae and the ichi gene from Bt israelensis. The Schi chitinase precursor is 688 amino acids long with an estimated molecular mass of 75.75 kDa and a theoretical isoelectric point of 5.74, and contains four domains, which are, in sequence, a signal peptide, an N-terminal catalytic domain, a fibronectin type III like domain and a C-terminal chitin-binding domain. Sequence comparison and the evolutionary relationship of the Bt sotto Schi chitinase to other chitinase and chitinase-like proteins are also discussed.