Understanding the mechanisms of multidrug transport proteins

多药转运蛋白泵送多种化合物穿过细胞膜，并在癌症化疗和感染性疾病的治疗中发挥重要作用。该项目的目标是解开两个多药转运蛋白，小多药耐药（SMR）蛋白EmrE和ATP结合盒（ABC）转运蛋白Sav 1866的结构-功能关系的机制。EmrE的具体目标是绘制底物识别和运输途径，并了解底物和质子运输之间耦合的能量和结构基础。此外，我将探讨蛋白质-脂质相互作用如何影响EmrE的结构和动力学，并研究蛋白质寡聚状态的功能作用。最终，我的目标是通过光开关脂质来控制EmrE的结构和低聚状态-从而控制其功能。对于Sav 1866，目标是表征向内和向外构象之间的过渡，并研究底物识别和易位。为了实现这些目标，我将使用分子动力学（MD）类型的计算机模拟，并与实验小组密切合作。除了应用传统的全原子分子动力学模拟，有效的多尺度模型将开发访问所需的空间和时间尺度。所概述的方法的成功应用将促进膜蛋白-脂质复合物的未来机理研究，并最终能够直接模拟脂质和蛋白质在小但功能性细胞单元（例如小囊泡）中的动态相互作用。

Multidrug transport proteins pump a wide range of compounds across the cell membrane and play an important role in cancer chemotherapy and the treatment of infectious diseases. The goal of this project is to unravel the structure-function relationships underlying the mechanisms of two multidrug transporters, the small multidrug resistance (SMR) protein EmrE and the ATP-binding cassette (ABC) transporter Sav1866. Specific aims for EmrE are to map the substrate recognition and transport pathways, and to understand the energetic and structural basis for the coupling between substrate and proton transport. Furthermore, I will probe how protein-lipid interactions influence the structure and dynamics of EmrE, and investigate the functional role of the protein oligomeric state. Ultimately, I aim at steering the structure and oligomeric state – and thereby the function – of EmrE through photoswitchable lipids. For Sav1866, the goal is to characterize the transition between the inward- and outward-facing conformations, and to study substrate recognition and translocation. To reach these aims, I will use molecular dynamics (MD) type computer simulations and closely collaborate with experimental groups. In addition to the application of conventional all-atom MD simulations, efficient multiscale models will be developed to access the required spatial and temporal scales. Successful application of the outlined approach will foster future mechanistic studies of membrane protein – lipid complexes, and ultimately enable to directly simulate the dynamic interplay of lipids and proteins in small but functional cellular units, such as small vesicles.