Molecular Cloning of the Transglutaminase Gene from Bacillus subtilis and Its Expression in Escherichia coli

We cloned and characterized a gene, tgl, encoding transglutaminase in Bacillus subtilis. The tgl gene contained a open reading frame 735-nucleotides long that encoded a 245-residue protein with the molecular weight of 28,300. The deduced amino acid sequence had little sequence similarity with sequences of other transglutaminases from a Streptoverticillium sp. or from mammals. The -10 and -35 regions of a putative promoter resembled the consensus sequence for the σ^K-dependent promoter. In addition, a sequence similar to the consensus sequence for the GerE binding site was found upstream from this region. These findings suggested that tgl was transcribed in the mother cells during a late stage of sporulation. Evidence for this suggestion was that transglutaminase activity was detected in sporulating cells during the same stage. Transglutaminase activity was detected in Escherichia coli cells transformed with a plasmid for expression of the tgl gene.