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Updated: May 17, 2026

Fluorescence Assays for the Study of Mycobacterium tuberculosis Interaction with the Immune Receptor SLAMF1
Published on: February 28, 2025
A lipid-dependent link between activity and oligomerization state of the M. tuberculosis SMR protein TBsmr
Karsten Mörs1, Ute A Hellmich, Daniel Basting
1Institute for Biophysical Chemistry, J.W. Goethe University, Frankfurt, Germany; Centre for Biomolecular Magnetic Resonance, J.W. Goethe University, Frankfurt, Germany.
Abstract:
TBsmr is a secondary active multidrug transporter from Mycobacterium tuberculosis that transports a plethora of compounds including antibiotics and fluorescent dyes. It belongs to the small multidrug resistance (SMR) superfamily and is structurally and functionally related to E. coli EmrE. Of particular importance is the link between protein function, oligomeric state and lipid composition. By freeze fracture EM, we found three different size distributions in three different lipid environments for TBsmr indicating different oligomeric states. The link of these states with protein activity has been probed by fluorescence spectroscopy revealing significant differences. The drug binding site has been probed further by (19)F-MAS NMR through chemical labeling of native cysteine residues showing a water accessible environment in agreement with the alternating access model.
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