Gene Cloning and Expression of the Catalase from the Hydrogen Peroxide-Resistant Bacterium Vibrio rumoiensis S-1 and Its Subcellular Localization

摘要

The catalase gene, vktA, of the hydrogen peroxide-resistant bacterium Vibrio rumoiensis S-1 has been isolated and sequenced. Plasmid pBSsa1 was obtained by genome library screening and it complemented a catalase-less mutant, Escherichia coli strain UM2, indicating that pBSsa1 contained the catalase gene (vktA). The vktA gene consisted of an open reading frame of 1530 bp encoding a 508 amino-acid protein with a calculated size of 57657.79 Da. the deduced amino acid sequence showed high homology with that of bacterial group III catalases. Investigation of the subcellular catalase localization using an immuno-electron microscopical technique revealed that a larger amount of VktA catalase is present in the periplasmic space than in the cytoplasm. The periplasmic space of this bacterium can therefore be regarded as reservior of VktA catalase in V. rumoiensis S-1.