Determination of the backbone torsion angle epsilon in nucleic acids.
The multiplet structure of cross peaks in double-quantum-filtered COSY NMR spectra is analysed for those resonances that include passive heteronuclear couplings. Interestingly, the cross peak involving the sugar-ring protons H2' and H3' in nucleic acids display an E. COSY-type appearance exclusively when the backbone torsion angle epsilon (C4'-C3'-O3'-P) adopts a gauche(-) conformation. This observation allows an unambiguous analysis of the conformation around epsilon, without the knowledge of 3JCP coupling constants.
Blommers
M J
MJ
Department of Physics, Ciba-Geigy AG, Basel, Switzerland.
Nanz
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D
Zerbe
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O
D001483:Base Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation