STRUCTURAL STUDIES OF GRAMICIDIN & OTHER SELF-ASSOCIATING PEPTIDES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们的目标是发展与H/D交换相结合的质谱学来研究多肽和蛋白质的缔合反应。因此，我们选择甘草苷作为我们的MS方法开发的对象，以研究多肽和蛋白质在溶液中的相互作用。Gramicidin是一种膜十五肽，起到通道的作用，允许单价金属离子通过，帮助细菌细胞死亡。活性形式是非共价结合的二聚体。研究这种多肽自组装的一种方法是比较多肽在各种溶剂中的状态，从亲水性(例如三氟乙醇)到疏水性(例如正丙醇)。我们正在研究使用电喷雾质谱仪来研究自关联。在不同的组织中。以及直接引入质谱仪的混合溶剂。二聚体(同位和异位)可以在引入气相和AMT后存活下来。在气相中，随着介电常数的减小而增加。常量。反映固相行为的溶剂。串联质谱仪数据显示，二聚体在气相中的稳定性随着金属离子尺寸的增加而降低，这有力地表明金属离子结合在二聚体内部的单体之间。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our goal is to develop mass spectrometry combined with H/D exchange to study peptide and protein association reactions. Therefore, we chose gramicidin as the subject of our method development of MS methods to study the association of peptides and proteins in solution. Gramicidin is a membrane pentadecapeptide that acts as a channel, allowing the passage of monovalent metal ions and assisting in bacterial cell death. The active form is a noncovalently bound dimer. One means to study the self-assembly of this peptide has been to compare the state of the peptide in various solvents ranging from hydrophilic (e.g., trifluoroethanol) to hydrophobic (e.g., n-propanol). We are investigating the use of electrospray mass spectrometry to study the self-assocn. of gramicidin in various org. and mixed solvents that are introduced directly into the mass spectrometer. The dimer (both homo and hetero) can survive the introduction into the gas phase, and the amt. in the gas phase increases with the decreasing dielec. const. of the solvent, reflecting soln.-phase behavior. Tandem mass spectrometry data reveal that the stability of dimer in the gas phase decreases with increasing metal ion size, strongly suggesting that the metal ion binds inside the dimer between the monomers.