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bioRxiv · 10.1101/2023.05.18.541325

Dynamic nuclear polarization illuminates key protein-lipid interactions in the native bacterial cell envelope

Kent, J. E.·Ackerman, B. E.·Debelouchina, G. T.·Marassi, F. M.
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Abstract

Elucidating the structure and interactions of proteins in native environments has become a fundamental goal of structural biology. Nuclear magnetic resonance (NMR) spectroscopy is well suited for this task but often suffers from low sensitivity, especially in complex biological settings. Here, we use a sensitivity-enhancement technique called dynamic nuclear polarization (DNP) to overcome this challenge. We apply DNP to capture the membrane interactions of the outer membrane protein Ail, a key component of the host invasion pathway of Yersinia pestis. We show that the DNP-enhanced NMR spectra of Ail in native bacterial cell envelopes are well resolved and enriched in correlations that are invisible in conventional solid-state NMR experiments. Furthermore, we demonstrate the ability of DNP to capture elusive interactions between the protein and the surrounding lipopolysaccharide layer. Our results support a model where the extracellular loop arginine residues remodel the membrane environment, a process that is crucial for host invasion and pathogenesis.

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Kent, J. E., Ackerman, B. E., Debelouchina, G. T., Marassi, F. M.. 2023-05-18. Dynamic nuclear polarization illuminates key protein-lipid interactions in the native bacterial cell envelope. https://doi.org/10.1101/2023.05.18.541325

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