Observation of internucleotide NH...N hydrogen bonds in the absence of directly detectable protons

Majumdar, A.; Kettani, A.; Skripkin, E.; Patel, D.

Авторы: Majumdar A., Kettani A., Skripkin E., Patel DJ
Журнал: Journal of Biomolecular NMR
Том: 15
Номер: 3
Год издания: 1999
Издательство: Springer Nature
Местоположение издательства: Switzerland
Первая страница: 207
Последняя страница: 211
Аннотация: Several structural motifs found in nucleic acids involve N-H...N hydrogen bonds in which the donor hydrogens are broadened to extinction due to chemical or conformational exchange. In such situations, it is impossible to use the well-established HNN-COSY or soft HNN-COSY experiments, which report the presence of the hydrogen bond directly on the donor proton(s). We present a pulse sequence, H(CN)N(H), for alleviating this problem in hydrogen bonds of the type NdH...Na-CH, in which the donor Nd nitrogen is correlated with the corresponding non-exchangeable C-H proton associated with the acceptor Na nitrogen. In this way, missing NdH...Na correlations in an HNN-COSY spectrum may be recovered from CH-Nd correlations in the H(CN)N(H) spectrum. By correlating a different set of nuclei relative to the HNN-COSY class of experiments, the H(CN)N(H) experiment also serves to remove ambiguities associated with degeneracies in HNN-COSY spectra. The technique is demonstrated on d(GGAGGAG)4,a quadruplex containing a novel A. (G.G.G.G). A hexad and on d(GGGCAGGT)4, containing a G.G.G.C tetrad, in which missing NH2...N7 correlations are retrieved via H8-(N2,N6) correlations in the H(CN)N(H) spectrum.
Добавил в систему: Скрипкин Евгений Алексеевич

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Observation of internucleotide NH...N hydrogen bonds in the absence of directly detectable protonsстатья