Molecular cloning of manganese catalase from Lactobacillus plantarum

A genomic clone encoding manganese-containing catalase has been isolated from lactic acid bacterium Lactobacillus plantarum, sequenced, and expressed in Escherichia coli cells with an inducible expression system. The primary structure of the enzyme deduced from the nucleotide sequence, that comprises 266 amino acid residues, showed no significant homology with that of any other proteins registered on the available data bases. No peptide motifs conserved among active sites of proteins including manganese-containing enzymes were found. The E. coli cells carrying an expression construct, in which the 5'-noncoding region of the manganese catalase gene was replaced with the lac promoter, highly induced a protein reacting with the antiserum to manganese catalase. The prediction of secondary structure from the deduced primary structure suggested that the L. plantarum manganese catalase, that is classified as a novel protein on the basis of its primary structure, has a main structural motif formed by four near parallel helices between which is the catalytic site manganese.