生物大分子波谱学原理 吴季辉 Side Chain Assignment (H)C(CO)NH-TOCSY: Side Chain C chemical shifts H(CC)(CO)NH-TOCSY: Side chain H chemical shifts HCCH-COSY: adjacent C-C correlation HCCH-TOCSY: long range C-C correlation within one residue 生物大分子波谱学原理 吴季辉 CCONH-TOCSY 生物大分子波谱学原理 吴季辉 HCONH-TOCSY 生物大分子波谱学原理 吴季辉 13C-13C相关谱 碳-碳相关谱 HCCH-COSY(1H-13C-13C-1H correlation spectroscopy) 及HCCH-TOCSY(1H-13C-13C-1H total correlation spectroscopy) 用于证认13C标记蛋白质的脂肪链1H及13C,信号传递是从1H开 始,经过单键J偶合到13C,再通过类似同核COSY及TOCSY的 机制传递到其他13C,最后通过单键J偶合回传到1H。所以这类 实验可以看作1H同核COSY及TOCSY在13C上的推广。除了可 以获得13C的信息,也可得到1H的信息,对于大蛋白质而言, 效果比1H同核COSY及TOCSY更好,因为在1H同核COSY及 TOCSY中起作用的是比较小的1H同核J偶合(一般小于10Hz), 而这里虽有三步传递,却均是比较大的J偶合,其中JHC约 140Hz,JCC约35Hz。因此这类实验对于大蛋白质的侧链1H, 13C的证认非常重要。 生物大分子波谱学原理 吴季辉 13C-13C相关谱 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 生物大分子波谱学原理 吴季辉 7.3 13C-13C相关谱 生物大分子波谱学原理 吴季辉 7.3 13C-13C相关谱 生物大分子波谱学原理 吴季辉 7.3 13C-13C相关谱 生物大分子波谱学原理 吴季辉 7.3 13C-13C相关谱 生物大分子波谱学原理 吴季辉 7.3 13C-13C相关谱 Conventional implementation: 1H magnetization is transferred in a refocused INEPT to 13C in-phase magnetization. After C,C-TOCSY mixing, the back-transfer is achieved in an analogous manner. The incrementation of delays required for shared-time evolution in t1 is also indicated. Note that the C' 180 pulse during the t1 evolution period is not absolutely required, because 2JH,C' couplings are small. Doubly sensitivity-enhanced 3D H(C)CH-TOCSY experiment with hetero-nuclear gradient echo for solvent suppression. The heteronuclear in-phase transfer is implemented with a yxzICOS-CT sequence. Four different combination of gradients and and of phase settings and (corresponding to echo/antiecho pathways for both indirect dimensions) have to be recorded and stored in different memory locations. Modifications required for a semi-constanttime evolution during t1 are indicated. The operator F is the sum of I operators denoting the proton spins