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-Structure paper
タイトル | Structure and mechanism of the Mrp complex, an ancient cation/proton antiporter. |
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ジャーナル・号・ページ | Elife, Vol. 9, Year 2020 |
掲載日 | 2020年7月31日 |
著者 | Julia Steiner / Leonid Sazanov / |
PubMed 要旨 | Multiple resistance and pH adaptation (Mrp) antiporters are multi-subunit Na (or K)/H exchangers representing an ancestor of many essential redox-driven proton pumps, such as respiratory complex I. ...Multiple resistance and pH adaptation (Mrp) antiporters are multi-subunit Na (or K)/H exchangers representing an ancestor of many essential redox-driven proton pumps, such as respiratory complex I. The mechanism of coupling between ion or electron transfer and proton translocation in this large protein family is unknown. Here, we present the structure of the Mrp complex from solved by cryo-EM at 3.0 Å resolution. It is a dimer of seven-subunit protomers with 50 trans-membrane helices each. Surface charge distribution within each monomer is remarkably asymmetric, revealing probable proton and sodium translocation pathways. On the basis of the structure we propose a mechanism where the coupling between sodium and proton translocation is facilitated by a series of electrostatic interactions between a cation and key charged residues. This mechanism is likely to be applicable to the entire family of redox proton pumps, where electron transfer to substrates replaces cation movements. |
リンク | Elife / PubMed:32735215 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.98 Å |
構造データ | EMDB-11027, PDB-6z16: |
化合物 | ChemComp-PTY: ChemComp-K: |
由来 |
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キーワード | MEMBRANE PROTEIN / Mrp antiporter / sodium/proton exchanger / bioenergetics / complex |