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Title | Ion transfer mechanisms in Mrp-type antiporters from high resolution cryoEM and molecular dynamics simulations. |
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Journal, issue, pages | Nat Commun, Vol. 13, Issue 1, Page 6091, Year 2022 |
Publish date | Oct 14, 2022 |
Authors | Yongchan Lee / Outi Haapanen / Anton Altmeyer / Werner Kühlbrandt / Vivek Sharma / Volker Zickermann / |
PubMed 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 ...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. |
External links | Nat Commun / PubMed:36241630 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.24 - 2.96 Å |
Structure data | EMDB-14124, PDB-7qru: EMDB-15593: Structure of Bacillus pseudofirmus Mrp antiporter complex, dimer EMDB-15693: Structure of Bacillus pseudofirmus Mrp antiporter complex, monomer, processed at original pixel size (0.837 A/pix) |
Chemicals | ChemComp-3PE: ChemComp-HOH: |
Source |
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Keywords | MEMBRANE PROTEIN / Antiporter / Electron transport / Complex |