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Publication Abstract from PubMed

Antibiotic-resistant bacterial pathogens pose an urgent healthcare threat, prompting a demand for new medicines. We report the mode of action of the natural ansamycin antibiotic kanglemycin A (KglA). KglA binds bacterial RNA polymerase at the rifampicin-binding pocket but maintains potency against RNA polymerases containing rifampicin-resistant mutations. KglA has antibiotic activity against rifampicin-resistant Gram-positive bacteria and multidrug-resistant Mycobacterium tuberculosis (MDR-M. tuberculosis). The X-ray crystal structures of KglA with the Escherichia coli RNA polymerase holoenzyme and Thermus thermophilus RNA polymerase-promoter complex reveal an altered-compared with rifampicin-conformation of KglA within the rifampicin-binding pocket. Unique deoxysugar and succinate ansa bridge substituents make additional contacts with a separate, hydrophobic pocket of RNA polymerase and preclude the formation of initial dinucleotides, respectively. Previous ansa-chain modifications in the rifamycin series have proven unsuccessful. Thus, KglA represents a key starting point for the development of a new class of ansa-chain derivatized ansamycins to tackle rifampicin resistance.

Mode of Action of Kanglemycin A, an Ansamycin Natural Product that Is Active against Rifampicin-Resistant Mycobacterium tuberculosis.,Mosaei H, Molodtsov V, Kepplinger B, Harbottle J, Moon CW, Jeeves RE, Ceccaroni L, Shin Y, Morton-Laing S, Marrs ECL, Wills C, Clegg W, Yuzenkova Y, Perry JD, Bacon J, Errington J, Allenby NEE, Hall MJ, Murakami KS, Zenkin N Mol Cell. 2018 Sep 12. pii: S1097-2765(18)30688-9. doi:, 10.1016/j.molcel.2018.08.028. PMID:30244835^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.