Polymorphisms of FtsK/SpoIIIE protein in Mycobacterium tuberculosis complex strains may affect both protein function and host immune reaction.

FtsK/SpoIIIE family ATPases are conserved throughout bacteria and are involved in the translocation of DNA and proteins through membrane-spanning pores. Through comparison of 26 whole-genome-sequenced M. tuberculosis complex (MTBC) strains downloaded from NCBI website, we found that FtsK/SpoIIIE protein presented polymorphisms. One M. bovis strain and three BCG strains even showed the two T cell epitopes missing. Then we chose 159 clinical M. tuberculosis isolates from China, amplified gene encoding FtsK/SpoIIIE protein (Rv3871) and compared the sequences. The results showed that there are polymorphisms existed in FtsK/SpoIIIE protein among MTBC, which may affect both protein function and host immune reaction. In addition, position 1497 could be used as a good phylogenetic marker for Beijing strains.