Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0307, USA.
J Magn Reson. 2009 Dec;201(2):121-30. doi: 10.1016/j.jmr.2009.08.012. Epub 2009 Sep 2.
(13)C-detected solid-state NMR experiments have substantially higher sensitivity than the corresponding (15)N-detected experiments on stationary, aligned samples of isotopically labeled proteins. Several methods for tailoring the isotopic labeling are described that result in spatially isolated (13)C sites so that dipole-dipole couplings among the (13)C are minimized, thus eliminating the need for homonuclear (13)C-(13)C decoupling in either indirect or direct dimensions of one- or multi-dimensional NMR experiments that employ (13)C detection. The optimal percentage for random fractional (13)C labeling is between 25% and 35%. Specifically labeled glycerol and glucose can be used at the carbon sources to tailor the isotopic labeling, and the choice depends on the resonances of interest for a particular study. For investigations of the protein backbone, growth of the bacteria on [2-(13)C]-glucose-containing media was found to be most effective.
(13)C 检测固态 NMR 实验比相应的（15）N 检测固定、定向同位素标记蛋白质样品的实验具有更高的灵敏度。本文描述了几种定制同位素标记的方法，这些方法产生空间分离的（13）C 位点，从而最小化（13）C 之间的偶极-偶极耦合，因此消除了在采用（13）C 检测的一维或多维 NMR 实验的间接或直接维度中对同核（13）C-（13）C 去耦的需求。随机分数（13）C 标记的最佳百分比在 25%到 35%之间。可以使用特定标记的甘油和葡萄糖作为碳源来定制同位素标记，选择取决于特定研究中感兴趣的共振。对于研究蛋白质骨架，发现细菌在含有[2-(13)C]-葡萄糖的培养基中的生长最有效。
