Molecular cloning, characterization, and heterologous expression of a new κ-carrageenase gene from marine bacterium Zobellia sp ZM-2

kappa-Carrageenases exhibit apparent distinctions in gene sequence, molecular weight, enzyme properties, and posttranslational processes. In this study, a new kappa-carrageenase gene named cgkZ was cloned from the marine bacterium Zobellia sp. ZM-2. The gene comprised an open reading frame of 1,638 bp and encoded 545 amino acids. The natural signal peptide of kappa-carrageenase was used successfully for the secretory production of the recombinant enzyme in Escherichia coli. A posttranslational process that removes an amino acid sequence of about 20 kDa from the C-terminal end of kappa-carrageenase was first discovered in E. coli. An increase in enzyme activity by 167.3 % in the presence of 5 mM DTT was discovered, and Na+ at a certain concentration range was positively correlated with enzyme activity. The kappa-carrageenase production of E. coli was 9.0 times higher than that of ZM-2. These results indicate the potential use of the enzyme in the biotechnological industry.