Laboratory of Protein Engineering and Vaccines, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
Shanxi Academy of Advanced Research and Innovation, Taiyuan 030032, China.
Proc Natl Acad Sci U S A. 2024 Oct 29;121(44):e2412653121. doi: 10.1073/pnas.2412653121. Epub 2024 Oct 23.
EfpA, the first major facilitator superfamily (MFS) protein identified in (Mtb), is an essential efflux pump implicated in resistance to multiple drugs. EfpA-inhibitors have been developed to kill drug-tolerant Mtb. However, the biological function of EfpA has not yet been elucidated. Here, we present the cryo-EM structures of EfpA complexed with lipids or the inhibitor BRD-8000.3 at resolutions of 2.9 Å and 3.4 Å, respectively. Unexpectedly, EfpA forms an antiparallel dimer. Functional studies reveal that EfpA is a lipid transporter and BRD-8000.3 inhibits its lipid transport activity. Intriguingly, the mutation V319F, known to confer resistance to BRD-8000.3, alters the expression level and oligomeric state of EfpA. Based on our results and the observation of other antiparallel dimers in the MFS family, we propose an antiparallel-function model of EfpA. Collectively, our work provides structural and functional insights into EfpA's role in lipid transport and drug resistance, which would accelerate the development of antibiotics against this promising drug target.
埃夫帕（EfpA）是在结核分枝杆菌（Mtb）中首次发现的主要易化超家族（MFS）蛋白之一，是一种与多种药物耐药性相关的必需外排泵。已经开发了埃夫帕抑制剂来杀死耐药结核分枝杆菌。然而，埃夫帕的生物学功能尚未阐明。在这里，我们展示了埃夫帕与脂质或抑制剂 BRD-8000.3 复合物的冷冻电镜结构，分辨率分别为 2.9 Å 和 3.4 Å。出乎意料的是，埃夫帕形成了一个反平行二聚体。功能研究表明，埃夫帕是一种脂质转运蛋白，BRD-8000.3 抑制其脂质转运活性。有趣的是，已知 V319F 突变赋予了对 BRD-8000.3 的抗性，改变了埃夫帕的表达水平和寡聚状态。基于我们的结果和 MFS 家族中其他反平行二聚体的观察，我们提出了埃夫帕的反平行功能模型。总之，我们的工作为埃夫帕在脂质转运和耐药性中的作用提供了结构和功能见解，这将加速针对这一有前途的药物靶标的抗生素的开发。
