SPIN-STATE-SELECTIVE EXCITATION - APPLICATION FOR E.COSY-TYPE MEASUREMENT OF J(HH) COUPLING-CONSTANTS

A new pulse sequence element, spin-state-selective excitation ((SE)-E- 3), is introduced and combined with E.COSY-type techniques for measure ment of H-1-H-1 J coupling constants, (SE)-E-3 edits the two resonance s of a doublet prior to an evolution period of a multidimensional expe riment and results in a subspectrum for each resonance, Due to this ed iting the large heteronuclear one-bond coupling constants normally exp loited for separation of submultiplets in E.COSY-type experiments can be suppressed in experiments employing (SE)-E-3. Hence there is a conc omitant effective increase in resolution, Apart from pulse imperfectio ns and relaxation during a delay (4J)(-1) (SE)-E-3 causes no loss of s ensitivity in comparison to conventional experiments. Experimental con firmation is done using the protein RAP 17-97 (N-terminal domain of al pha(2)-macroglobulin receptor associated protein). (C) 1997 Academic P ress.