Side Chain Assignment HCCONHTOCSY Side Chain C chemical

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

Conventional implementation: 1 H magnetization is transferred in a refocused INEPT to 13 C 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 t 1 is also indicated. Note that the C' 180 pulse during the t 1 evolution period is not absolutely required, because 2 JH, C' couplings are small.

Doubly sensitivity-enhanced 3 D H(C)CH-TOCSY experiment with hetero-nuclear gradient echo for solvent suppression. The heteronuclear in-phase transfer is implemented with a yxz. ICOS-CT sequence. Four different combination of gradients 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 t 1 are indicated. The operator F is the sum of I operators denoting the proton spins