Costeira-Paulo J, Gault J, Popova G, Ladds MJGW, van Leeuwen IMM, Sarr M, Olsson A, Lane DP, Laín S, Marklund EG, Landreh M
Cell Chem Biol 25 (3) 309-317.e4 [2018-03-15; online 2018-01-18]
The interactions between proteins and biological membranes are important for drug development, but remain notoriously refractory to structural investigation. We combine non-denaturing mass spectrometry (MS) with molecular dynamics (MD) simulations to unravel the connections among co-factor, lipid, and inhibitor binding in the peripheral membrane protein dihydroorotate dehydrogenase (DHODH), a key anticancer target. Interrogation of intact DHODH complexes by MS reveals that phospholipids bind via their charged head groups at a limited number of sites, while binding of the inhibitor brequinar involves simultaneous association with detergent molecules. MD simulations show that lipids support flexible segments in the membrane-binding domain and position the inhibitor and electron acceptor-binding site away from the membrane surface, similar to the electron acceptor-binding site in respiratory chain complex I. By complementing MS with MD simulations, we demonstrate how a peripheral membrane protein uses lipids to modulate its structure in a similar manner as integral membrane proteins.
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