Structural and chemical biology of membrane proteins

我们的实验室研究了一些完整的膜蛋白家族的功能的结构基础。我们将X射线结晶学与功能分析与一系列生化和生物物理技术相结合来探讨这些问题。1)钾离子选择性通道(K通道)是一大群不同的完整的膜蛋白，对细胞的正常功能至关重要。动物毒液中的毒素通过与不同部位结合，能够通过特定的钾通道亚型特异性地抑制离子传导，因此成为神经科学中不可缺少的工具。然而，在缺乏带有K通道的毒素复合体的晶体结构的情况下，特定毒素识别特定K通道的结构基础仍然不清楚。我的博士后工作导致了K通道和蝎子毒素之间的第一个复合体的晶体结构。目前，我们正在用其他毒素，特别是从蛇毒中分离出来的树突毒素来研究K通道的结构。K通道的不同部分是毒素的靶标，因此每一类不同类型的毒素-通道复合体的结构将导致对这些非常重要的一类离子通道的独特方面及其在细胞生理中的作用的深入了解。2)在第二个项目中，我们将注意力集中在将铁带入线粒体的线粒体内膜转运蛋白上。随后，铁被用于血红素的生物合成，血红素是血红蛋白、肌红蛋白和细胞色素中的血红素的中心成分，铁-硫簇是蛋白质参与广泛的细胞活动所需的重要辅因子。呼吸链复合体中的电子传递、调节传感、光合作用和DNA修复。我们目前正在使用异源表达来获得足够的纯化材料，用于生化和生物物理表征。

Our laboratory investigates the structural bases of functions of a number of integral membrane protein families. We combine x-ray crystallography together with functional analyses with a range of biochemical and biophysical techniques to approach these problems. 1) Potassium‐selective channels (K+ channels) are a large, diverse group of integral membrane proteins, crucial for proper cellular functioning. Toxins from animal venoms are able to specifically inhibit ion‐conduction by specific K+ channel subtypes by binding to different parts, and have thus emerged as indispensible tools in neuroscience. However, in the absence of a co‐crystal structure of a toxin‐complex with a K+ channel, the structural bases for recognition of specific K+ channels by specific toxins remain obscure. My postdoctoral work resulted in the first crystal structure of a complex between a K+ channel and a toxin from scorpion venom. Currently we are pursuing the structures of K+ channels with other toxins, specifically, Dendrotoxin, isolated from snake venom. Different parts of K+ channels are targeted by toxins, and thus structure of each distinct class of toxin-channel complexes will lead to insights about unique aspects of these very important class of ion channels and their role in cellular physiology. 2) In a second project, we are focusing our attention on mitochondrial inner membrane transporters that bring iron into mitochondria. Subsequently, the iron is utilized in the biosynthesis of heme, a central component of the heme in hemoglobin, myoglobin, and cytochromes , and iron-sulfur clusters, important cofactors required for proteins involved in a wide range of cellular activities, viz. electron transport in respiratory chain complexes, regulatory sensing, photosynthesis and DNA repair. We are currently using heterologous expression to obtain enough purified material for biochemical and biophysical characterization.