DETERMINATION OF 3J(C,P) AND 3J(H,P) COUPLING-CONSTANTS IN NUCLEOTIDEOLIGOMERS WITH FIDS-HSQC

A method for measuring J(C,P) and J(H,P) coupling constants is present ed, based on fitting a target multiplet containing the heteronuclear c oupling to a reference multiplet that lacks the heteronuclear coupling . In DNA and RNA oligonucleotides, information on backbone torsion ang les can be obtained from these couplings. Experimental multiplets are obtained from P-31-coupled and P-31-decoupled H-1, C-13 HSQC spectra o f Rp-cyclic methylphosphonate. The accuracy to which the heteronuclear coupling constants can be determined depends on the signal-to-noise r atio of the experimental data and is analyzed in detail.