Engineered MATE multidrug transporters reveal two functionally distinct ion-coupling pathways in NorM from Vibrio...

Area of Science:

• Biochemistry
• Molecular Biology
• Microbiology

Background:

• Multidrug and toxic compound extrusion (MATE) transport proteins are crucial for multidrug resistance in pathogens and influence drug metabolism in mammals.
• Existing knowledge of MATE transporter mechanisms relies heavily on structural data and molecular dynamics simulations, with limited understanding of transport energetics.
• While most MATE transporters use proton (H+) or sodium (Na+) gradients, NorM-VC from Vibrio cholerae exhibits dual energy coupling capabilities.

Purpose of the Study:

• To investigate the energy transduction mechanisms of the NorM-VC transporter from Vibrio cholerae.
• To elucidate the specific roles of different protein domains in H+ and Na+ translocation pathways.
• To understand how NorM-VC adapts its energy coupling to environmental changes, such as salinity fluctuations.

Main Methods:

• Engineering of chimeric MATE transporters by fusing N- and C-lobes of NorM-VC and NorM-PS.
• Construction and analysis of mutant transporter variants.
• Conducting drug binding and transport assays using wildtype and engineered transporters.

Main Results:

• Chimeric and mutant transporters provided insights into the localization and organization of ion translocation pathways.
• Demonstrated the versatile energy coupling capabilities of NorM-VC, utilizing both H+ and Na+ gradients.
• Highlighted the functional plasticity of NorM-VC in response to varying energy sources.

Conclusions:

• The study elucidates the adaptable energy coupling mechanisms of NorM-VC.
• Findings suggest that NorM-VC's dual ion dependency allows adaptation to diverse environmental conditions, including fluctuating salinity.
• This research deepens the understanding of MATE transporter function and energy transduction in biological systems.