RESPIRATORY VIRUS ION CHANNELS

平均每年有10%到20%的美国人 感染了流感病毒，但唯一的抗病毒治疗 甲型流感病毒感染者可使用的药物是金刚乙胺， 其靶标是M2离子通道蛋白。更有效 需要该通道的抑制剂， 突变体产生得很快。 在上一个补助期，我们发现 当细胞质的pH值 域降低，并与M2形成过渡金属络合物 分子。 我们建议确定这些抑制的机制 以确定药物作用于M2分子的新靶点。 从功能测量中，我们发现， M2离子通道是同源四聚体，我们已经鉴定出 内衬孔道。 我们建议确定的结构， 直接测量分子的结构信息， 将允许设计更有用的抑制剂。 个人 目标是：1.了解M2离子的抑制机制 由于C-末端结构域的pH值降低，导致了通道。2.到 确定具有取代的M2离子通道孔结构 半胱氨酸可及性法3.利用过渡金属配合物 探测M2离子通道的孔结构。4.应用该方法 M2离子通道跨膜的定点自旋标记 结构域，以确定其静息结构和结构变化， 发生在低pH值激活。为了理解 跨膜组氨酸37在通过M2离子通道的质子转运中的作用。 6.在一组单独的实验中，我们将检验以下假设： B型流感病毒的NB蛋白具有离子通道的功能。

During an average year, 10-20 percent of the US population becomes infected with influenza virus, but the only antiviral treatment available for those infected with influenza A virus is rimantadine, the target for which is the M2 ion channel protein. More effective inhibitors of the channel are needed because rimantadine-resistant mutants are generated rapidly. In the previous grant period we found that inhibition of the channel occurs when the pH of the cytoplasmic domain is lowered and transition metal complexes are formed with the M2 molecule. We propose to determine the mechanism for these inhibitions in order to identify new targets for drug action on the M2 molecule. From functional measurements we have found that the active state of the M2 ion channel is a homotetramer and we have identified residues that line the channel pore. We propose to determine the structure of the molecule with direct measurements because this structural information will allow for the design of more useful inhibitors. The individual aims are: 1. To understand the mechanism for inhibition of M2 ion channel as a result of decreased pH of the C-terminal domain. 2. To determine the M2 ion channel pore structure with the substituted cysteine accessibility method. 3. To use transition metal complexes to probe the pore structure of the M2 ion channel. 4. To apply the approach of site-directed spin labeling of the M2 ion channel transmembrane domain to determine its resting structure and structural changes that occur on activation by low pH. 5. To understand the role of transmembrane histidine 37 in proton transport by the M2 ion channel. 6. In a separate set of experiments we will test the hypothesis that the NB protein of influenza B virus functions as an ion channel.