Cloning of the lysA gene from Mycobacterium tuberculosis

The lysA and proC genes of Mycobacterium tuberculosis were cloned by screening of a recombinant lambda gt11 M. tuberculosis DNA library for phages able to complement lysA and proC Escherichia coli mutants. The lysA gene encodes diaminopimelic acid decarboxylase which catalyzes the conversion of diaminopimelic acid (DAP) to lysine. The lysA gene from M. tuberculosis encodes a 44-kDa protein, as determined by maxicell experiments. The nucleotide sequence of the structural gene was established. The deduced amino acid sequence was found to exhibit significant homology (from 55% to 73% similarity, and from 27% to 53% identity) to DAP decarboxylase sequences from other bacterial species.