Peptide antibiotic that functions through inhibition of the bacterial DNA-dependent RNA polymerase (RNAP) (PubMed:21396375, PubMed:30626643). Inhibits transcription by binding in RNAP secondary channel, where it sterically blocks the folding of the trigger loop, which is essential for efficient catalysis (PubMed:21396375, PubMed:30626643). In contrast to MccJ25, does not restrict access of nucleotide substrates to the catalytic center and shows a non-competitive mode of inhibition (PubMed:30626643). Shows activity against closely related Gram-negative Burkholderia and Pseudomonas strains (PubMed:18671394). Is not active against Gram-positive bacteria (PubMed:18671394). Highly thermostable. Is composed of a ring composed by 9 residues, and a tail of 10 residues (Probable). The peptide is threaded when the C-terminal tail is inserted throught the isopeptide-bonded ring (Probable). It is assumed that the two processing enzymes CapB/CapC convert the precursor protein CapA into the mature lasso peptide capistruin. CapB is assumed to cleave the precursor protein CapA and to set an N-terminal Gly free, whose a-NH2 group acts as the nucleophile in the subsequent cyclization reaction. CapC is most likely involved in the side-chain carboxyl group activation of aspartic acid at position 9 generating the electrophile for the condensation reaction. CapD may export capistruin outside of the producing cells.