Lee 2022 Nat Commun

Lee Y, Haapanen O, Altmeyer A, Kühlbrandt W, Sharma V, Zickermann V (2022) Ion transfer mechanisms in Mrp-type antiporters from high resolution cryoEM and molecular dynamics simulations. https://doi.org/10.1038/s41467-022-33640-y

» Nat Commun 13:6091. PMID: 36241630 Open Access

Lee Yongchan, Haapanen Outi, Altmeyer Anton, Kuehlbrandt Werner, Sharma Vivek, Zickermann Volker (2022) Nat Commun

Abstract: Multiple resistance and pH adaptation (Mrp) cation/proton antiporters are essential for growth of a variety of halophilic and alkaliphilic bacteria under stress conditions. Mrp-type antiporters are closely related to the membrane domain of respiratory complex I. We determined the structure of the Mrp antiporter from Bacillus pseudofirmus by electron cryo-microscopy at 2.2 Å resolution. The structure resolves more than 99% of the sidechains of the seven membrane subunits MrpA to MrpG plus 360 water molecules, including ~70 in putative ion translocation pathways. Molecular dynamics simulations based on the high-resolution structure revealed details of the antiport mechanism. We find that switching the position of a histidine residue between three hydrated pathways in the MrpA subunit is critical for proton transfer that drives gated trans-membrane sodium translocation. Several lines of evidence indicate that the same histidine-switch mechanism operates in respiratory complex I.

• Bioblast editor: Plangger M

Labels: MiParea: mt-Structure;fission;fusion 

Enzyme: Complex I