Cloning, sequencing and expression of the gene for alpha antigen from Mycobacterium intracellulare and use of PCR for the rapid identification of Mycobacterium intracellulare.

The complete nucleotide sequence of alpha antigen secreted from Mycobacterium intracellulare (ATCC13950) was determined. The gene encoded 330 amino acids including 40 amino acids for signal peptide, followed by 290 amino acids for a mature protein with molecular mass 30,645 Da. The cloned gene was expressed in Escherichia coli by using an E. coli expression vector. Based on these results, the feasibility of rapid identification of M. intracellulare by two step polymerase chain reaction (PCR) was demonstrated.