Method of multidimensional NMR with simultaneous plural magnetization transfer, and NMR pulse sequence thereof
There is disclosed an NMR measurement method of observing plural magnetization transfer patterns in one experiment and observing their respective time-modulated, evolved chemical shifts. In an earlier portion of a pulse sequence, a transition is made from in-phase magnetizations to antiphase magnetizations using RF pulses. In an intermediate portion of the sequence, the antiphase magnetizations are interchanged using 90° RF pulses. In a later portion of the sequence, a transition is made from the antiphase magnetizations to the in-phase magnetizations using other RF pulses. Simultaneously with the interchange of the magnetizations, evolution of chemical shifts is performed by a constant-time evolution technique. In the earlier and later portions of the pulse sequence, evolutions of the chemical shifts can be performed simultaneously because the magnetizations of two nuclei are in lateral magnetization state.
1. A method of multidimensional NMR measurement, comprising the steps of applying first transition, intermediate exchanging and second transition pulse sequences and detecting plural time-modulated magnetization transfer pathways simultaneously if such plural magnetization transfer pathways exist from excitation of magnetization to observation,
wherein said plural magnetization transfer pathways includes at least a first magnetization transfer pathway going from a first nucleus to a second nucleus and a second magnetization transfer pathway going from the second nucleus to the first nucleus, with the magnetization transfer caused by at least one of J-coupling and dipole-dipole interaction, and wherein time modulations of the at least first and second magnetization transfer pathways are observed simultaneously, with the time modulation caused by evolution of chemical shifts or residual dipolar couplings.
2. The method of multidimensional NMR measurement as set forth in claim 1 , wherein said first nucleus is peptide-coupled amide 15 N nucleus, while said second nucleus is peptide-coupled 13 C nucleus in the alpha position.
3. The method of multidimensional NMR measurement according to claim 1 , comprising:
providing a first pulse sequence for making a transition from in-phase magnetization of a first nucleus or in-phase magnetization of a second nucleus magnetically coupled to said first nucleus to antiphase magnetization of said first nucleus magnetically coupled to said second nucleus or antiphase magnetization of said second nucleus coupled to said first nucleus;
providing a second pulse sequence for exchanging the antiphase magnetization of said first nucleus coupled to said second nucleus or the antiphase magnetization of said second nucleus coupled to said first nucleus for the antiphase magnetization of said second nucleus coupled to said first nucleus or the antiphase magnetization of said first nucleus coupled to said second nucleus, said second pulse sequence succeeding said first pulse sequence; and
providing a third pulse sequence for making a transition from the antiphase magnetization of said second nucleus coupled to said first nucleus or the antiphase magnetization of said first nucleus coupled to said second nucleus to the in-phase magnetization of said second nucleus coupled to said first nucleus or the in-phase magnetization of said first nucleus coupled to said second nucleus, said third pulse sequence succeeding said second pulse sequence,
wherein said first and third pulse sequences cause evolution of chemical shifts for a given period.
4. The method of multidimensional NMR measurement according to claim 3 , wherein said first nucleus is peptide-coupled amide 15 N nucleus, while said second nucleus is peptide-coupled 13 C nucleus in the alpha position.
5. The method of multidimensional NMR measurement according to claim 3 , wherein during measurement of peptide coupling, said first pulse sequence induces a transition from in-phase magnetization of 15 N to antiphase magnetization of 15 N 13 C α (where N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from in-phase magnetization of 13 C α to antiphase magnetization of 13 C α 15 N.
6. The method of multidimensional NMR measurement according to claim 3 , wherein during measurement of peptide coupling, said second pulse sequence induces a transition from antiphase magnetization of NC α to antiphase magnetization of 13 C α 15 N (where 15 N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from antiphase magnetization of 13 C α 15 N to antiphase magnetization of 15 N 13 C α .
7. The method of multidimensional NMR measurement according to claim 3 , wherein during measurement of peptide coupling, said third pulse sequence induces a transition from antiphase magnetization of 13 C α 15 N to in-phase magnetization of 13 C α (where 15 N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from antiphase magnetization of 15 N 13 C α to in-phase magnetization of 15 N.
8. The method of multidimensional NMR measurement according to claim 4 , wherein during measurement of peptide coupling, said first pulse sequence induces a transition from in-phase magnetization of 15 N to antiphase magnetization of 15 N 13 C α (where N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from in-phase magnetization of 13 C α to antiphase magnetization of 13 C α 15 N.
9. The method of multidimensional NMR measurement according to claim 4 , wherein during measurement of peptide coupling, said second pulse sequence induces a transition from antiphase magnetization of NC α to antiphase magnetization of 13 C α 15 N (where 15 N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from antiphase magnetization of 13 C α 15 N to antiphase magnetization of 15 N 13 C α .
10. The method of multidimensional NMR measurement according to claim 4 , wherein during measurement of peptide coupling, said third pulse sequence induces a transition from antiphase magnetization of 13 C α 15 N to in-phase magnetization of 13 C α (where 15 N is amide nitrogen nucleus of peptide coupling and 13 C α is carbon nucleus of peptide coupling in the alpha position) and, at the same time, induces a transition from antiphase magnetization of 15 N 13 C α to in-phase magnetization of 15 N.