STRUCTURAL STUDIES OF GRAMICIDIN & OTHER SELF-ASSOCIATING PEPTIDES

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 我们的目标是发展质谱结合H/D交换研究肽和蛋白质缔合反应。因此，我们选择短杆菌肽作为我们MS方法开发的主题，以研究溶液中肽和蛋白质的缔合。短杆菌肽是一种膜十五肽，作为通道，允许单价金属离子通过并协助细菌细胞死亡。 活性形式是非共价结合的二聚体。 研究这种肽的自组装的一种方法是比较肽在各种溶剂中的状态，从亲水性（例如，三氟乙醇）到疏水的（例如，正丙醇）。 我们正在研究使用电喷雾质谱来研究自缔合。在各种有机和混合溶剂中的短杆菌肽，直接引入质谱仪。 二聚体（均聚体和杂聚体）可以在引入气相后继续存在，而amt。在气相中，随着扩散系数的减小而增加。溶剂的常数，反射溶液-相行为 串联质谱数据显示，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，强烈表明金属离子在单体之间的二聚体内部结合。

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.