Cryo-electron microscopy reveals the pentameric structure and dimerisation of MscL in Escherichia coli, indicating how channel clustering modulates bacterial osmotic stress responses.
Key Points
To resolve the high-resolution structure of Escherichia coli mechanosensitive channel of large conductance (EcMscL) in a lipid membrane-mimetic environment and clarify its oligomeric organization.
Reconstituted purified EcMscL into lipid nanodiscs.
Determined the experimental structure using single-particle cryo-electron microscopy at 3.1 Å resolution.
Solved a 3.1 Å pentameric channel structure featuring a cytosolic hydrophobic gate, a periplasmic cavity, and unique conformations in the periplasmic loop.
Identified a periplasmic dimeric interface connecting pentamers via residues 61–63.
Observed that pentamer dimerisation supports fluid-like mosaic channel packing with 5.9–9 nm centre-to-centre distances, explaining higher-order cluster formation.