Vicinal¹³C^–15N coupling constants in peptides

Abstract

Vicinal 13C-15N coupling constants for three 15N-labelled peptide models having Cp-Ca-CISN dihedral angles constrained to 110 or 160' are smaller than 1 Hz, which minimizes their potential utility in peptide conformation studies.

15N–13C spin–spin coupling constants in some aniline derivatives

“…This represents another example of a very small 3J(15N,13C) value (23,46). Hz, similar to the value observed in acrylamide (46).…”

Applicability of vicinal heteronuclear (13C‐1H, 15N‐1H, 13C‐15N) coupling constants for conformational analysis of amino acids: Phenylalanine, α‐aminobutyric acid and β‐alanine

“…As far as the 'J(CN) values are concerned, the results obtained so far (Ref. 13 and this study) give few grounds for optimism concerning the applicability of this parameter for the conformational analysis of amino acids and peptides, especially on taking into account the considerable experimental requirements for obtaining such data.…”

“…INDO calculations indicate a strong dependence of 3J(NH) on the electron lonepair orientation.' There have been only a few attempts to use 3J(NH) for the conformational analysis of amino acid^.^^'^ Whereas the experimental measurement of 3J(NH) is relatively easy when "N-enriched 13 * Author to whom correspondence should be addressed. compounds are used," this is not true in the case of 3J(CN).…”

Syntheses, conformation, and reactions of cyclic peptides

“…However, the NMR determination of another internal rotation angle, if, is very difficult. Blasi and Kopple (44) tried to obtain information about ~ from the CO-N three-bond-coupling constant. They investigated the 1 s N_C, Ca_C # coupling constant with Cyclo-(Gly-Pro) and Cyclo-(Gly-Phe) where ~b angles are confined to 155 ° and 110 °, respectively.…”