Molecular Cloning and Expression of a Novel Chitinase Gene from Vibrio sp. 98CJ11027

Abstract

The chiK gene encoding chitinase ChiK was isolated from a marine bacterium, Vibrio sp. 98CJ11027. We amplified a partial sequence of the chiK using chitinase-specific primer sets. Using inverse PCR cloning method with two specific sets of PCR primers rather than single set, we identified the 4 kb DNA fragment containing chiK gene. From the fragment, we amplified the full chiK gene and cloned into pUC18 vector designated as pChiK. The recombinant E. coli clones harboring pChiK produced a clear zone around the colony in the colloidal chitin plates. Open reading frame of the chiK is 2553 bp long encoding a ChiK precursor protein of 851 amino acids, which consist of N-terminal signal peptide of 21 amino acids and a mature ChiK protein with 830 amino acids. The deduced amino acid sequences of chiK shows 89% identity with that of Vibrio carchariae chitinase. The conserved module of Vibrio sp. 98CJ11027 ChiK indicates that the ChiK belongs to the family 18 of glycoside hydrolases.