Adenylyl cyclase in Mycobacterium tuberculosis H37Rv—A possible virulence factor

Eukaryotic-like adenylyl cyclase has been identified in Mycobacterium tuberculosis H37Rv. The M. tuberculosis adenylyl cyclase gene ( cya ) was cloned by complementation of a cAMP dependent expression of maltose operon in a cya deletion E. coli strain. The nucleotide sequence analysis of the cya gene revealed an open reading frame that coded for 443 amino acids. A comparison of M. tuberculosis adenylyl cyclase with the protein sequences in the data bank revealed its homology to the eukaryotic Type I and the calmodulin responsive adenylyl cyclases with an average of about 40% identical and 60% similar amino acids in the catalytic domain. The occurrence of eukaryotic-like adenylyl cyclase in M. tuberculosis suggests a role for this important enzyme in cell signaling and perhaps in the pathogenesis of M. tuberculosis . We suggest that the human pathogen M. tuberculosis might have acquired the eukaryotic cya by a recombination event.