3JCOHA
KARPLUS
Empirical 3JCO-HA values and angular backbone constraints can be interconverted following well-known Karplus relationships.

3JCO-HA=3.62*cos2(fi+120) - 2.11*cos(fi+120) + 1.29 ( 96JACS2483 )
3JCO-HA=3.76*cos2(fi+120) - 1.63*cos(fi+120) + 0.89 ( 99JB1-14 )

where fi is the backbone torsion angle.

VALUES
 The expected 3JCO-HA coupling constants values found in the secondary structure of proteins:
MEASUREMENT
13C,15N-labeled proteins
RELATED TOPICS
The same dihedral angle information can be obtained from other coupling constants values:

 

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