H-Exchange Rates and Hydrogen Bonding of Individual Peptide NH Protons in Alpha-Helices

鲍德温博士首次提出衡量汇率 单个肽NH质子在单个分离的α- 螺旋 核磁共振（NMR）技术将被 使用，基于一维质子的15 N光谱编辑 江西篇章 单个肽NH将通过化学方法被15 N标记。 肽的合成和15 N自旋回波差谱 将用于给出单个15 N标记的1H光谱 肽NH。 一个试验性的实验证明了 已经采取了这种做法。 新方法将用于测试 螺旋-无规卷曲转变理论的基本假设，以及 还提供了有关汇率的背景资料， 单α-螺旋中的酰胺质子，用于解释数据 蛋白质折叠中间体。 %%% 这些实验将为获得 关于短肽的结构信息，例如，当 肽与特定受体复合。 目前还 广泛的兴趣“肽库”，无论是在生物技术 在生物医学领域，一般来说。 方法论一直是 用来合成不同短的天文数字 肽序列，然后选择少量的 可以特异性结合信号受体的序列 转导途径 这种方法将提供一种重要的工具 用于表征肽受体中肽的结构 复杂. 如上所述，该方法还具有直接 应用于表征动力学结构的问题 蛋白质折叠途径的中间体。

Dr. Baldwin proposes to measure, for the first time, exchange rates of individual peptide NH protons within single, isolated alpha- helices. A nuclear magnetic resonance (NMR) technique will be used, based on 15N spectral editing of the one-dimensional proton spectrum. A single peptide NH will be 15N-labeled by chemical synthesis of the peptide, and 15N spin echo difference spectroscopy will be used to give the 1H spectrum of the single 15N-labeled peptide NH. A trial experiment demonstrating the feasibility of this approach has been made. The new method will be used to test the basic assumptions of helix-random coil transition theory, and also to provide background information about exchange rates of amide protons in single alpha-helices, for use in interpreting data on protein folding intermediates. %%% The proposed experiments will provide a new technique for obtaining structural information about short peptides, for example, when the peptide is complexed with a specific receptor. Currently there is wide interest in " peptide libraries", both in the biotechnology field and in biomedical science generally. Methodologies have been developed for synthesizing astronomical numbers of different short peptide sequences and then for selecting a small number of sequences that can bind specifically to a receptor in a signal transduction pathway. This method will provide an important tool for characterizing the structure of a peptide in a peptide-receptor complex. As pointed out above, the method also has direct application to the problem of characterizing structures of kinetic intermediates on the pathway of protein folding.