(8/8) I am incredibly grateful to everyone who made this work possible @medcambridge.bsky.social @mrclmb.bsky.social ‬@cambiochem.bsky.social

Thanks to Lalita, Ben and Meindert for their guidance and support. Jan + Tanmay for their EM wizardry and all members of the Ramakrishnan/Luisi labs
#ENDTB

(7/8) Worryingly, we found variants in MmpL5 that increase bedaquiline resistance. These variants haven’t been seen clinically… so far

Bedaquiline is a drug the world cannot afford to lose

We hope this will prompt urgent development of efflux-avoiding BDQ derivatives and new efflux pump inhibitors

(6/8) Using three independent genetic approaches, we identified variants in MmpL5 that both increase and decrease bedaquiline efflux. These variants converge on a site the lower periplasmic cavity of MmpL5 that we propose is the binding site of bedaquiline.

(5/8) @janboehning.bsky.social and @tbharat-lab.bsky.social ‬ did cryo-ET on Mtb. We find that the coiled-coil domain is only long enough to reach the Peptidoglycan-Arabinogalactan layer. A strongly conserved surface at the tip of MmpL5 hints at the presence of an elusive mycomembrane partner 🤔

(4/8) MmpL5 proteins often have a puzzling 13 nm long coiled coil inserted in their periplasmic domain that is essential for efflux.

Using AlphaFold2, we found that this domain forms an unusual methionine-lined tube to transport substrates across the periplasm.

(3/8) Surprisingly, we found that the trimer interface is mediated by phospholipids (which might explain why purifying this had proved so challenging 😥). The acpM protein that co-purifies with MmpL5 sandwiches its Phosphopantetheine group into the subunit interface…

(2/8) Our cryo-EM structure revealed that MmpS5L5 has a novel trimeric architecture distinct from the classic AcrAB-TolC pumps found in Gram-negative bacteria.

Mycobacteria always like to do things differently…

(8/8) I am incredibly grateful to everyone who made this work possible
@medcambridge.bsky.social @mrclmb.bsky.social @cambiochem.bsky.social

Thanks to Lalita, Ben and Meindert for their guidance and support. Jan + Tanmay for their EM wizardry and all members of the Ramakrishnan/Luisi labs

#ENDTB

(7/8) Worryingly, we found variants in MmpL5 that increase bedaquiline resistance. These variants haven’t been seen clinically… so far

Bedaquiline is a drug the world cannot afford to lose

We hope this will prompt urgent development of efflux-avoiding BDQ derivatives and new efflux pump inhibitors

(5/8) @janboehning.bsky.social ‬ and @tbharat-lab.bsky.social did cryo-ET on Mtb. We found that the coiled-coil domain is only long enough to reach the Peptidoglycan-Arabinogalactan layer. A strongly conserved surface at the tip of MmpL5 hints at the presence of an elusive mycomembrane partner 🤔