RESUMO
In this paper we demonstrate experimentally that the continuously phase-modulated homonuclear decoupling sequence DUMBO-1 is suitable for high-resolution proton NMR spectroscopy of rigid solids. Over a wide range of experimental conditions, we show on the model sample L-alanine as well as on small peptides that proton linewidths of less than 0.5 ppm can be obtained under DUMBO-1 decoupling. In particular the DUMBO-1 sequence yields well resolved proton spectra both at slow and fast MAS. The DUMBO-1 decoupling scheme can in principle be inserted in any multi-nuclear or multi-dimensional solid-state NMR experiment which requires a high-resolution 1H dimension. An example is provided with the 13C-1H MAS-J-HMQC experiment.
Assuntos
Algoritmos , Espectroscopia de Ressonância Magnética/métodos , Ressonância Magnética Nuclear Biomolecular/métodos , Proteínas/química , Prótons , Processamento de Sinais Assistido por Computador , Alanina/química , Carbono , Isótopos de Carbono , Cristalografia/métodos , Ciclosporina/química , Dipeptídeos/química , Magnetismo , Ressonância Magnética Nuclear Biomolecular/instrumentação , Pós , Conformação Proteica , Controle de Qualidade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Marcadores de SpinRESUMO
In this article a method is suggested for restricting a sample (spatial localization) by preparing the magnetization with a phase-modulated radiofrequency pulse which inverts magnetization only over a very narrow range of radiofrequency field strengths. This is the most efficient method, in terms of sensitivity, of restricting the sample to improve rf homogeneity. The method is demonstrated by using it to improve the resolution obtained in a homonuclear dipolar decoupling experiment.
