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-Structure paper
タイトル | Proton-coupled transport mechanism of the efflux pump NorA. |
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ジャーナル・号・ページ | Nat Commun, Vol. 15, Issue 1, Page 4494, Year 2024 |
掲載日 | 2024年5月27日 |
![]() | Jianping Li / Yan Li / Akiko Koide / Huihui Kuang / Victor J Torres / Shohei Koide / Da-Neng Wang / Nathaniel J Traaseth / ![]() |
PubMed 要旨 | Efflux pump antiporters confer drug resistance to bacteria by coupling proton import with the expulsion of antibiotics from the cytoplasm. Despite efforts there remains a lack of understanding as to ...Efflux pump antiporters confer drug resistance to bacteria by coupling proton import with the expulsion of antibiotics from the cytoplasm. Despite efforts there remains a lack of understanding as to how acid/base chemistry drives drug efflux. Here, we uncover the proton-coupling mechanism of the Staphylococcus aureus efflux pump NorA by elucidating structures in various protonation states of two essential acidic residues using cryo-EM. Protonation of Glu222 and Asp307 within the C-terminal domain stabilized the inward-occluded conformation by forming hydrogen bonds between the acidic residues and a single helix within the N-terminal domain responsible for occluding the substrate binding pocket. Remarkably, deprotonation of both Glu222 and Asp307 is needed to release interdomain tethering interactions, leading to opening of the pocket for antibiotic entry. Hence, the two acidic residues serve as a "belt and suspenders" protection mechanism to prevent simultaneous binding of protons and drug that enforce NorA coupling stoichiometry and confer antibiotic resistance. |
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手法 | EM (単粒子) |
解像度 | 3.26 - 3.61 Å |
構造データ | EMDB-41605, PDB-8tte: EMDB-41606, PDB-8ttf: EMDB-41607, PDB-8ttg: EMDB-41608, PDB-8tth: |
由来 |
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![]() | TRANSPORT PROTEIN / Protonated NorA / efflux pump / MRSA / TRANSPORT PROTEIN/IMMUNE SYSTEM / E222QD307N NorA / TRANSPORT PROTEIN-IMMUNE SYSTEM complex / E222Q NorA / D307N NorA |