The Structure and Interactions of Periplasmic Domains of Crucial MmpL Membrane Proteins from Mycobacterium tuberculosis.
Mycobacterium tuberculosis mycobacterial membrane protein large (MmpL) proteins are important in substrate transport across the inner membrane. Here, we show that MmpL proteins are classified into two phylogenetic clusters, where MmpL cluster II contains three soluble domains (D1, D2, and D3) and has two full-length members, MmpL3 and MmpL11. Significantly, MmpL3 is currently the most druggable M. tuberculosis target. We have solved the 2.4-Å MmpL11-D2 crystal structure, revealing structural homology to periplasmic porter subdomains of RND (multidrug) transporters. The resulting predicted cluster II MmpL membrane topology has D1 and D2 residing, and possibly interacting, within the periplasm. Crosslinking and biolayer interferometry experiments confirm that cluster II D1 and D2 bind with weak affinities, and guided D1-D2 heterodimeric model assemblies. The predicted full-length MmpL3 and MmpL11 structural models reveal key substrate binding and transport residues, and may serve as templates to set the stage for in silico anti-tuberculosis drug development.
Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA.
Nicholas
N
Chim
Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA.
Rodrigo
R
Torres
Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA.
Yuqi
Y
Liu
The Pasarow Mass Spectrometry Laboratory, NPI-Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90024, USA.
Joe
J
Capri
Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA.
Gaëlle
G
Batot
The Pasarow Mass Spectrometry Laboratory, NPI-Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90024, USA.
Julian P
JP
Whitelegge
Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, UCI, Irvine, CA 92697, USA. Electronic address: celia.goulding@uci.edu.
Celia W
CW
Goulding
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D019897:Periplasm / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C000599913:MmpL3 protein, Mycobacterium tuberculosis
MmpL; Mycobacterium tuberculosis; RND transporters; X-ray crystallography; biolayer interferometry; crosslinking; porter domain; tuberculosis