Protein NMR. J(CO-CO) Coupling Constants

³J_COCO

KARPLUS

Empirical ³J_CO-CO values and angular backbone constraints can be interconverted following well-known Karplus relationships:

³J_CO-CO= 1.33*cos²(fi) - 0.88*cos(fi) + 0.62 ( 96JACS8170 ) ³J_CO-CO= 1.51*cos²(fi) - 1.09*cos(fi) + 0.39 ( 99JB1-14 )
where fi is the backbone torsion angle.

VALUES

³J_CO-CO are smaller than 2.5 Hz

MEASUREMENT

Using the quantitative J-correlation approach with 3D HN(CO)CO and 3D (HN)CO(CO)NH experiments.
3D H(N)CA,CO[CO]-E.COSY in ¹³C,¹⁵N-labeled proteins in H₂O.
Application of in the study of side-chain conformation in an unfolded protein ( 99JMB705 ).

RELATED TOPICS

The same dihedral angle information can be obtained from other coupling constants values:

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