MEMBRANE PEPTIDE STRUCTURE VIA NMR & QUANTUM CHEMISTRY

SIR提供L-[2-13C]色氨酸；2g L：色氨酸；1.25g这个项目背后的想法是让 13C标记的甘草素，作为膜穿透的原型 多肽/蛋白质片段，并使用 各向同性碳-13化学SHIF‘F，加上量子化学，作为 结构的探查。以前的工作总是集中在定向上 (15N，2H，一些13C)信息-直线在 定向样品，而不是完全分析化学位移 使用量子化学，这就是我们在这里建议的。一种能力 从结构角度分析蛋白质的各向同性化学位移 有很好的机会让可能的系统更容易 考察，甘草素中色氨酸的Ca、Cb、Cg应为优良 探测(特别是因为TRP在功能上意义重大)。通过 将观察到的各向同性化学位移与量子相结合 化学计算的屏蔽表面，对于TRP来说，可以获得 C1，c2的解，以及Val，Leu的f，y，c1结果。这些 独特的解决方案消除了与可能的偶极或 四极形派生几何约束，ANS与 通常，更准确的(但多值的)张量数据应该会产生非常 精确、独特的核磁共振解决方案，适用于f、y、ci、c2。TRP知识 方向对于理解语法动作很重要，并且 以上结果与我们计划获得的结果(一起) 商业上可获得的13C甘氨酸和丙氨酸)应该一起 清楚地表明了化学位移在结构研究中的作用， 尤其是因为，在某种意义上，化学位移是最 基本的核磁共振性质。

The SIR provided L-[2- 13 C]Tryptophan; 2g L-13- 13C]Tryptophan; 1.25g The idea behind this project is to make 13C-labeled gramicidins, as prototypical membrane penetrating peptide/protein fragments, and to explore their structure using the ISOTROPIC CARBON- 13 CHEMICAL SHIF'F, plus quantum chemistry, as a probe of structure. Previous work has always focused on orientational (15N, 2H, some 13C) information - the position of a line in an oriented sample, rather than completely analyzing chemical shifts using quantum chemistry, which is what we propose here. The ability to analyze isotropic chemical shifts in proteins in structural terms has a good chance of making may more systems amenable to investigation, and Ca, Cb, Cg of Trp in gramicidin should be excellent probes (especially since the Trps are functionally significant). By combining the observed isotropic chemical shifts with the quantum chemically computed shielding surfaces, one obtains for Trp the solutions for c 1, c2 as well as f, y, c 1 results for Val, Leu. These unique solutions remove problems associated with may dipolar or quadrupolar derived geometry restraints, ans when combined with the often more accurate (but multivalued) tensor data should yield very accurate, unique NMR solutions, for f, y, c I, c2. Knowledge of Trp orientations is important for understanding gramicidin action, and the above results (together) with those we are planning to obtain with commercially available 13C glycines and alanines) should together clearly indicate the utility of chemical shifts in structure studies, especially since the chemical shift is, in a sense, the most fundamental NMR property.