Structure and interactions of the Voltage-Dependent Anion Channel(VDAC)

描述（由申请人提供）：电压依赖性阴离子通道（VDAC）介导小分子和离子穿过真核生物线粒体外膜的运输。有三种异构体与小分子和蛋白质有不同的相互作用。其中包括Bcl-2家族的促凋亡和抗凋亡成员，并且VDAC的不同亚型已被暗示在细胞凋亡中发挥作用，例如线粒体退出通道的形成或抑制。最近，我们获得了核磁共振分配并确定了洗涤剂胶束中人类VDAC-1的溶液结构（Hiller et al., 2008）。VDAC已经有30年的历史了，并且有许多关于其相互作用和功能方面的报道。通过最近对VDAC-1的核磁共振表征，我们现在能够验证这些报告并阐明该通道的功能。本研究的目的是研究VDAC异构体的结构、相互作用和功能。具体目标是：比较VDAC-1在LDAO胶束和磷脂纳米盘中的结构和相互作用，以评估胶束和双层环境之间的差异。2. 确定VDAC-2的结构，它包含一个n端扩展，并具有与VDAC-1不同的功能。3. 确定Bcl-2型蛋白的膜/胶束结合结构，研究VDAC复合物。4. 表征致病菌中VDAC与孔蛋白PorB的复合物。

DESCRIPTION (provided by applicant): The voltage-dependent anion channel (VDAC) mediates trafficking of small molecules and ions across the eukaryotic outer mitochondrial membrane. There are three isoforms that have distinct reported interactions with small molecules and proteins. These include pro- and anti-apoptotic members of the Bcl-2 family, and the different isoforms of VDAC have been implied to play roles in apoptosis, such as formation or inhibition of the mitochondrial exit channel. Recently, we obtained NMR assignments and determined the solution structure of human VDAC-1 in detergent micelles (Hiller et al., 2008). VDAC has been known for thirty years and numerous reports of interactions and functional aspects have been reported. With the recent NMR characterization of VDAC-1 we are now in a position to validate these reports and elucidate the function of the channel. The goal of the proposed research is to study the structure, interactions and function of VDAC isoforms. We will pursue the following specific aims: 1. Compare structure and interactions of VDAC-1 in LDAO micelles and phospholipids nanodiscs to assess differences between micelle and bilayer environments. 2. Determine the structure of VDAC-2, which contains an N-terminal extension and has reported functions distinct from VDAC-1. 3. Determine the membrane/micelle-bound structures of Bcl-2 type proteins and study VDAC complexes. 4. Characterize complexes of VDAC with the porin PorB from pathogenic bacteria. PUBLIC HEALTH RELEVANCE: We will study the solution structure of the human voltage-dependent anion channel (VDAC) in the membrane mimicking phospholipids nanodiscs and compare it with our recent structure obtained in LDAO micelles. We will also determine the structure of the VDAC-2 isoform, which has been shown to stabilize an inactive form of the Bak protein and may play a crucial role in controlling the onset of apoptosis. We also will investigate interactions of VDAC with Bcl-2-type proteins, bacterial pathogens and small molecules.