Department of Pharmacology, University of Cambridge, Cambridge, UK.
University College Dublin Clinical Research Centre, St. Vincent's University Hospital, Dublin, Ireland.
Commun Biol. 2021 May 11;4(1):558. doi: 10.1038/s42003-021-02081-6.
Multidrug and toxic compound extrusion (MATE) transport proteins confer multidrug resistance on pathogenic microorganisms and affect pharmacokinetics in mammals. Our understanding of how MATE transporters work, has mostly relied on protein structures and MD simulations. However, the energetics of drug transport has not been studied in detail. Many MATE transporters utilise the electrochemical H or Na gradient to drive substrate efflux, but NorM-VC from Vibrio cholerae can utilise both forms of metabolic energy. To dissect the localisation and organisation of H and Na translocation pathways in NorM-VC we engineered chimaeric proteins in which the N-lobe of H-coupled NorM-PS from Pseudomonas stutzeri is fused to the C-lobe of NorM-VC, and vice versa. Our findings in drug binding and transport experiments with chimaeric, mutant and wildtype transporters highlight the versatile nature of energy coupling in NorM-VC, which enables adaptation to fluctuating salinity levels in the natural habitat of V. cholerae.
多药和毒性化合物外排（MATE）转运蛋白赋予致病微生物多药耐药性，并影响哺乳动物的药代动力学。我们对 MATE 转运蛋白如何工作的理解主要依赖于蛋白质结构和 MD 模拟。然而，药物转运的能量学尚未得到详细研究。许多 MATE 转运蛋白利用电化学 H 或 Na 梯度来驱动底物外排，但霍乱弧菌的 NorM-VC 可以利用两种形式的代谢能。为了剖析 NorM-VC 中 H 和 Na 转运途径的定位和组织，我们设计了嵌合蛋白，其中 Pseudomonas stutzeri 的 H 偶联 NorM-PS 的 N 结构域与 NorM-VC 的 C 结构域融合，反之亦然。我们在与嵌合、突变和野生型转运蛋白的药物结合和转运实验中的发现突出了 NorM-VC 中能量偶联的多功能性质，这使其能够适应霍乱弧菌自然栖息地中不断变化的盐度水平。
