A protein backbone [psi] and [phi] angle dependence of 2J N (i) ,C[alpha]1;( i - 1): The new NMR experiment and quantum chemical calculations

A new pulse sequence exploiting double- and zero-quantum evolution of two-spin ^sup 15^N-^sup 13^C' coherence is proposed for the accurate measurements of ^sup 2^J^sub N(^ ^sub i^ ^sub ),Cα(^ ^sub i -^ ^sub 1)^ coupling constants. Application of the new experiment is presented for ^sup 13^C,^sup 15^N-labeled ubiquitin sample. The density functional theory calculations of ^sup 2^J^sub N(^ ^sub i^ ^sub ),Cα(^ ^sub i -^ ^sub 1)^ coupling constants have been performed to study their dependence on both ψ(i - 1) and Φ(i - 1) angle in model peptides, and the results exhibit a good correlation with experimental data.[PUBLICATION ABSTRACT]