Abstract

The gene of psychrophilic catalase BNC from Antarctic Bacillus sp. N2a was cloned by degenerate PCR and inverse PCR. BNC gene revealed a 1,461 bp open reading frame for a protein with 486 amino acids. The phylogenetic tree based on the amino acid sequences of BNC and representative psychrophilic microbial catalases manifested that BNC belonged to the Group III of the monofunctional catalase. The active-site residues of the structure-determined catalase were highly conserved in BNC. Comparison of the amino acid composition of BNC with its mesophilic homologue from Bacillus subtilisTE124 showed that BNC had properties of a cold-active enzyme.

Key words: Antarctic Bacillus, monofunctional catalase, cold-adapted enzymes, gene cloning.