Peptides inhibit DevR-regulated promoter activity. Effect of peptides on Rv3134c and sigA promoter activity in M.tb cultures was assessed under hypoxic (A) and aerobic (B) conditions. The data represents the mean ± SD of two independent experiments. * denotes a significant difference (p < 0.05) in the activity of Rv3134c and sigA promoters under hypoxic and aerobic conditions based on a Students’ t-test. For example, DevRS A peptide-mediated inhibition (at 5 mM concentration) of the Rv3134c promoter under hypoxic and aerobic conditions is ~ 45% and 14%, which is significantly higher than ~ 14% and 6% inhibition of sigA promoter activity under identical conditions. # denotes a significant difference (p <0.05) in Rv3134c promoter activity under hypoxic and aerobic conditions based on a Student’s t-test. For example, DevRS A peptide-mediated inhibition (at 2.5 mM and 5 mM concentration) under hypoxia is 30% and 45%, which is significantly higher than 5% & 15% inhibition observed under aerobic conditions. '0’ values on top of some bars indicate no detectable inhibition. Non-specific inhibition of transcription (measured using sigA promoter reporter plasmid) was not observed for two peptides, DevRS A-ext and DevRS D peptides.