Structural and functional characterization of Mycobacterium tuberculosis VapBC52 (Rv2514c-Rv2515c) toxin-antitoxin system reveals role in bacterial physiology and phage defence.

For RNA-seq experiments, early-log phase cultures (OD600nm ~ 0.2-0.3) of M. tuberculosis strains lacking vapBC52 locus that harbors either pTetRint or pTetRint-vapC52 were induced with the addition of 50 ng/ml Atc for 24 h. For total RNA isolation, induced cultures were harvested by centrifugation, washed twice with 1x PBS and lysed by bead beating in Trizol.

Total RNA was extracted by phenol-chloroform, precipitated with isopropanol and eluted using Qiagen RNA isolation kit as per manufacturer’s instructions. We report that VapC52 resulted in increased transcripts levels of proteins involved in cell wall and cell processes, several transfer RNA (tRNA) were also observed to be markedly decreased in the overexpression strain of M. tuberculosis.