alpha&beta HSQC, an HSQC-type experiment with improved resolution for I2S groups

被引:24
作者
Sattler, M
Schleucher, J
Schedletzky, O
Glaser, SJ
Griesinger, C
Nielsen, NC
Sorensen, OW
机构
[1] UNIV FRANKFURT,INST ORGAN CHEM,D-60439 FRANKFURT,GERMANY
[2] AARHUS UNIV,DEPT CHEM,DK-8000 AARHUS,DENMARK
[3] NOVO NORDISK AS,DK-2880 BAGSVAERD,DENMARK
关键词
D O I
10.1006/jmra.1996.0070
中图分类号
O64 [物理化学(理论化学)、化学物理学]; O56 [分子物理学、原子物理学];
学科分类号
070203 ; 070304 ; 081704 ; 1406 ;
摘要
A new HSQC-type pulse scheme is introduced that effectively improves the spectral resolution by what corresponds to the size of geminal J(HH) coupling constants, i.e., on the order of -14 Hz in CH2 groups of peptides and proteins. The gain in resolution comes from the fact that, in I2S groups with I-spin detection, only those resonances with the passive I spin being in either the alpha or the beta state are excited. The experiment alpha&beta HSQC has two versions: one that is alpha and beta selective in the echo and antiecho parts, respectively, or the opposite combination. This selection of polarizing only one half of the I-spin resonances works even when the two I spins are strongly coupled. Pure-absorption, selective alpha HSQC or beta HSQC spectra are obtained by the two combinations of the echo part of one of the alpha&beta HSQC spectra with the antiecho part of the other. These two spectra (alpha HSQC and beta HSQC) can be merged into another spectrum, Mab HSQC, which has the appearance of an HSQC spectrum with homonuclear broadband decoupling of geminal scalar interactions. The method is demonstrated on aqueous solutions of a decapeptide at the natural-abundance level of isotopes and on the protein rhodniin (103 residues) uniformly labeled with C-13 and N-15. (C) 1996 Academic Press, Inc.
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页码:171 / 179
页数:9
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