β Scribed by Marcel Ottiger; Frank Delaglio; Ad Bax
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Simple procedures are described for recording complementary be in excellent agreement with those of direct measurement in-phase and antiphase J-coupled NMR spectra. The sum and of 1 J NH splittings and E.COSY measurement of 2 J HNC = .
difference of these spectra contain only the upfield and the down-Conceptually the simplest possible way to generate a 1 Hfield components of a doublet, making it possible to measure the coupled [ 15 N, 1 H] correlation spectrum containing only the J splitting directly from these combinations without an increase upfield (or downfield) 15 N doublet component is to add two in resonance overlap relative to the decoupled spectrum. The apspectra: one recorded with in-phase doublets and one with proach is demonstrated for measurement of 1 J NH splittings and antiphase doublets. For short, we refer to this as the IPAP 2 J HNC = splittings in oriented and isotropic ubiquitin. Dipolar couapproach. The regular 1 H-coupled [ 15 N, 1 H] heteronuclear plings obtained from differences in the splittings measured in the single quantum correlation (HSQC) (14) generates in-phase oriented and isotropic phases are in excellent agreement with dipodoublets in the F 1 dimension. For a 15 N spin, S, at an angular lar couplings obtained from direct measurement of the splitting or from a conventional E.COSY-type measurement.
offset frequency d, coupled to its amide proton, I, antiphase S spin magnetization, 2I z S y , is generated at the end of the first INEPT transfer. This then evolves according to
π SIMILAR VOLUMES
(1)H-detected two-dimensional double-/zero-quantum experiments are described for measurement of homonuclear (2)J(HH)-couplings of NH(2) or CH(2) groups in proteins. These experiments utilize multiple-quantum coherence for determination of the size and the absolute sign of the geminal scalar and dipo
switched-angle sample spinning (SASS) (13); however, this By comparing experimental and calculated two-dimenis limited to situations where the isotropic spectra have only sional anisotropic chemical-shift/heteronuclear dipolar coua few resonances and is technically demanding because of pling [separa