Analysis of the oligomeric state of mycobacterial membrane protein large 3 and its interaction with SQ109 with native cell membrane nanoparticles system.

Mycobacterial membrane protein large 3 (Mmpl3) as a trehalose monomycolate lipid transporter contributes to cell wall biosynthesis. Inhibition of Mmpl3 can suppress cell growth and lead to mycobacterial death. SQ109 is a hydrophobic inhibitor of Mmpl3. We have devised a detergent-free strategy to characterize the SQ109/Mmpl3 interaction using the Native Cell Membrane Nanoparticles (NCMN) system, a new method for extracting membrane proteins that better retains native lipids. The homogeneity of the Mmpl3 NCMN particles was confirmed with electron microscopy. The hydrophobic protein-ligand interaction analysis shown for Mmpl3 using the NCMN system may broadly apply to other membrane proteins.