tagetitoxin

Tagetitoxin is a bacterial phytotoxin produced by Pseudomonas syringae pv. tagetis. It is a small molecule that acts as a potent and selective inhibitor of RNA polymerases. Tagetitoxin preferentially inhibits eukaryotic RNA polymerase III at low micromolar concentrations and also inhibits chloroplast RNA polymerase and bacterial multisubunit RNA polymerases in vitro[1][2][3][7]. The compound interferes with the development of chloroplasts in young plant leaves by inhibiting chloroplast RNA synthesis, leading to chlorosis[3][7]. Mechanistically, tagetitoxin binds within the active site of target RNA polymerases and blocks both initiation and elongation phases of transcription as well as pyrophosphorolysis; it may act by stabilizing an inactive conformation or mimicking pyrophosphate to inhibit enzyme translocation along DNA[6][7]. Tagetitoxin has not been approved for clinical use in humans or animals; its primary significance is as a biochemical tool for studying transcription mechanisms.

Other names

(1R,4R,5R,6R,7S,8R)-6-Acetoxy-7-amino-4-carbamoyl-4-hydroxy-8-(phosphonooxy)-9-oxa-3-thiabicyclo[3.3.1]nonane-1-carboxylic acid