SynopsisWe report the assignment of the backbone 'H-and 31P-nmr lines in the synthetic hexadeoxyribonucleotide pentaphosphate duplex d(GCATGC),, using double quantum filtered 'H-lH correlation spectroscopy, 'H observed IH3P heteronuclear correlation spectroscopy, and 31P relayed 'H-IH correlation spectroscopy. The strategy used enables one to make sequence-specific resonance assignments without reference to a known or assumed conformation of the DNA fragment.

A new 2D NMR pulse sequence for E.COSY-type measurement of J(HH) coupling constants is introduced. It exploits a heteronuclear spin, e.g., 13C, for displacement in the omega(1) frequency dimension via a large heteronuclear J coupling. The experiment is demonstrated by application to a heptapeptide at the natural abundance 13C level. It is suitable, for example, for measurement of 3J(HH) and 4J(HH) coupling constants in peptides and proteins.