| Structural highlights
Function
MMPL3_MYCS2 Transports trehalose monomycolate (TMM) to the cell wall (PubMed:31239378, PubMed:22520756, PubMed:28698380). Flips TMM across the inner membrane. Membrane potential is not required for this function (PubMed:28698380). Transports probably phosphatidylethanolamine (PE) as well. Binds specifically both TMM and PE, but not trehalose dimycolate (TDM). Binds also diacylglycerol (DAG) and other phospholipids, including phosphatidylglycerol (PG), phosphatidylinositol (PI), and cardiolipin (CDL) (PubMed:31113875). Contributes to membrane potential, cell wall composition, antibiotic susceptibility and fitness (PubMed:28703701).[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The mycobacterial membrane protein large 3 (MmpL3) transporter is essential and required for shuttling the lipid trehalose monomycolate (TMM), a precursor of mycolic acid (MA)-containing trehalose dimycolate (TDM) and mycolyl arabinogalactan peptidoglycan (mAGP), in Mycobacterium species, including Mycobacterium tuberculosis and Mycobacterium smegmatis. However, the mechanism that MmpL3 uses to facilitate the transport of fatty acids and lipidic elements to the mycobacterial cell wall remains elusive. Here, we report 7 structures of the M. smegmatis MmpL3 transporter in its unbound state and in complex with trehalose 6-decanoate (T6D) or TMM using single-particle cryo-electron microscopy (cryo-EM) and X-ray crystallography. Combined with calculated results from molecular dynamics (MD) and target MD simulations, we reveal a lipid transport mechanism that involves a coupled movement of the periplasmic domain and transmembrane helices of the MmpL3 transporter that facilitates the shuttling of lipids to the mycobacterial cell wall.
Structures of the mycobacterial membrane protein MmpL3 reveal its mechanism of lipid transport.,Su CC, Klenotic PA, Cui M, Lyu M, Morgan CE, Yu EW PLoS Biol. 2021 Aug 12;19(8):e3001370. doi: 10.1371/journal.pbio.3001370., eCollection 2021 Aug. PMID:34383749[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Varela C, Rittmann D, Singh A, Krumbach K, Bhatt K, Eggeling L, Besra GS, Bhatt A. MmpL genes are associated with mycolic acid metabolism in mycobacteria and corynebacteria. Chem Biol. 2012 Apr 20;19(4):498-506. doi: 10.1016/j.chembiol.2012.03.006. PMID:22520756 doi:http://dx.doi.org/10.1016/j.chembiol.2012.03.006
- ↑ Xu Z, Meshcheryakov VA, Poce G, Chng SS. MmpL3 is the flippase for mycolic acids in mycobacteria. Proc Natl Acad Sci U S A. 2017 Jul 25;114(30):7993-7998. doi:, 10.1073/pnas.1700062114. Epub 2017 Jul 11. PMID:28698380 doi:http://dx.doi.org/10.1073/pnas.1700062114
- ↑ McNeil MB, Dennison D, Parish T. Mutations in MmpL3 alter membrane potential, hydrophobicity and antibiotic susceptibility in Mycobacterium smegmatis. Microbiology (Reading). 2017 Jul;163(7):1065-1070. doi: 10.1099/mic.0.000498., Epub 2017 Jul 21. PMID:28703701 doi:http://dx.doi.org/10.1099/mic.0.000498
- ↑ Su CC, Klenotic PA, Bolla JR, Purdy GE, Robinson CV, Yu EW. MmpL3 is a lipid transporter that binds trehalose monomycolate and phosphatidylethanolamine. Proc Natl Acad Sci U S A. 2019 May 21. pii: 1901346116. doi:, 10.1073/pnas.1901346116. PMID:31113875 doi:http://dx.doi.org/10.1073/pnas.1901346116
- ↑ Fay A, Czudnochowski N, Rock JM, Johnson JR, Krogan NJ, Rosenberg O, Glickman MS. Two Accessory Proteins Govern MmpL3 Mycolic Acid Transport in Mycobacteria. mBio. 2019 Jun 25;10(3). pii: mBio.00850-19. doi: 10.1128/mBio.00850-19. PMID:31239378 doi:http://dx.doi.org/10.1128/mBio.00850-19
- ↑ Su CC, Klenotic PA, Cui M, Lyu M, Morgan CE, Yu EW. Structures of the mycobacterial membrane protein MmpL3 reveal its mechanism of lipid transport. PLoS Biol. 2021 Aug 12;19(8):e3001370. PMID:34383749 doi:10.1371/journal.pbio.3001370
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