3JCA-HN
KARPLUS
Empirical 3JCA-HN coupling constants should to a first approximation only depend on the torsion angle w. In fact, due to the planarity of the peptide bond, this coupling constant has no large variation in magnitude, showing a preferable trans conformation (equivalent to w=179.8 degrees) ( 97JACS6360 ). However, it has been shown that the size of 3JCA-HN depends on the variation in backbone angle phi and can be used to differentiate netween values of phi typical for alpha and beta structures ( 00JACS6268 ).
VALUES
The observable 3JCA-HN values fall in the range 0.0 to 1.0 Hz with a mean value of 0.5(+-0.3) Hz
MEASUREMENT
  • 3D HNCO[CA] experiment ( 00JACS6268 ) that uses the E.COSY principles.
  • 2D F1-spin-edited 1H-15N HSQC-type experiment ( 04JACS6232 )
  • 3D HCN experiment for perdeuterated proteins ( 03JACS44 )
    • RELATED TOPICS
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