7ph4
AMP-PNP bound nanodisc reconstituted MsbA with nanobodies, spin-labeled at position T68CAMP-PNP bound nanodisc reconstituted MsbA with nanobodies, spin-labeled at position T68C
Structural highlights
FunctionMSBA_ECOLI Involved in lipid A export and possibly also in glycerophospholipid export and for biogenesis of the outer membrane. Transmembrane domains (TMD) form a pore in the inner membrane and the ATP-binding domain (NBD) is responsible for energy generation. Publication Abstract from PubMedMembrane proteins are currently investigated after detergent extraction from native cellular membranes and reconstitution into artificial liposomes or nanodiscs, thereby removing them from their physiological environment. However, to truly understand the biophysical properties of membrane proteins in a physiological environment, they must be investigated within living cells. Here, we used a spin-labeled nanobody to interrogate the conformational cycle of the ABC transporter MsbA by double electron-electron resonance. Unexpectedly, the wide inward-open conformation of MsbA, commonly considered a nonphysiological state, was found to be prominently populated in Escherichia coli cells. Molecular dynamics simulations revealed that extensive lateral portal opening is essential to provide access of its large natural substrate core lipid A to the binding cavity. Our work paves the way to investigate the conformational landscape of membrane proteins in cells. The ABC transporter MsbA adopts the wide inward-open conformation in E. coli cells.,Galazzo L, Meier G, Januliene D, Parey K, De Vecchis D, Striednig B, Hilbi H, Schafer LV, Kuprov I, Moeller A, Bordignon E, Seeger MA Sci Adv. 2022 Oct 14;8(41):eabn6845. doi: 10.1126/sciadv.abn6845. Epub 2022 Oct , 12. PMID:36223470[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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