Dipole-Dipole Cross-Correlation in Proteins

Dipole-Dipole Cross-Relaxation

The dipole tensor between two spins (i and j) is axially symmetric with the axis of symmetry collinear to the bond defined as the internuclear vector ij. The structural implication of the angular dependence of the interaction of two dipole tensors ij and kl is therefore straightforward. Thus, the cross-correlated relaxation rates between two separate dipolar relaxation interactions has been used to measure dihedral angles between interatomic bond vectors without requirement of a predefined Karplus relation ( 97SCI1230 , 00JMR45-143 ).
Thus, the measurement of projection angles between internuclear bond vectors (ij and kl) from relaxation rates of DQ and ZQ coherences of ik spin pair provides useful angular restraints in biomolecules. It is based on the cross-correlated dipole-dipole relaxation mechanism which depends on the projection angle between dipoles and lineraly on the overall rotational correlation time.
Several applications have been reported:

DD cross-correlated relaxation rates Application

HN-N/CA-HA Measurement of backbone torsion angles in proteins ( 98JACS9880 , 99JB375 , 99JB277 , 99JACS6876 , 00JMR45-143 and , 02JB291-24) and in a weakly binding ligand-receptor complex ( 99JACS1949 ) . Also concerted use with 3J(CACA) ( 00JACS12017 ) and other cross-correlation rates (02JB349-22)

HN-N/HN-HA Identification of amino acids residues with positive fi angles as well as providing fi angle restraints fro glycine residues ( 00JACS2968 .

CA-HA/CA-HA Measurement of backbone torsion angles in a protein ( 00JACS1758 and 01CPC539).

H-C/H-C
Determination sugar puckering in nucleic acids
Study of sidechains dynamics in proteins ( 98JB165 , 01JB1-20 , 03JB151-27 and 04JB103-28 ).
Measurement of the chi1 torsion angle (99JACS3555 and 03JB151-27 ).
Study of methylene (CH2) and CH2D spin systems (98JMB939 and 04JMR202-166)
Probe of beta-sheet geometry (02JACS11038)

Study of unfolded proteins ( 98JMB939 and 99JACS3555 )
Derivation of CC dihedral angles in a natural product-protein complex (03ANG2515)

H-H/H-C Determination the relative orientation of a small allylpalladium complex ( 98ANG1903 ).
Study of methyl relaxation in proteins ( 04JB369-29 )

H-N/N-CO ( 99JACS9165 )

H-N/H-N (03JB265-25)

Also see cross-correlated DD-CSA and cross-correlated CSA-CSA rates.

DD cross-correlated relaxation rates	Application
HN-N/CA-HA	Measurement of backbone torsion angles in proteins ( 98JACS9880 , 99JB375 , 99JB277 , 99JACS6876 , 00JMR45-143 and , 02JB291-24) and in a weakly binding ligand-receptor complex ( 99JACS1949 ) . Also concerted use with 3J(CACA) ( 00JACS12017 ) and other cross-correlation rates (02JB349-22)
HN-N/HN-HA	Identification of amino acids residues with positive fi angles as well as providing fi angle restraints fro glycine residues ( 00JACS2968 .
CA-HA/CA-HA	Measurement of backbone torsion angles in a protein ( 00JACS1758 and 01CPC539).
H-C/H-C	Determination sugar puckering in nucleic acids Study of sidechains dynamics in proteins ( 98JB165 , 01JB1-20 , 03JB151-27 and 04JB103-28 ). Measurement of the chi1 torsion angle (99JACS3555 and 03JB151-27 ). Study of methylene (CH2) and CH2D spin systems (98JMB939 and 04JMR202-166) Probe of beta-sheet geometry (02JACS11038) Study of unfolded proteins ( 98JMB939 and 99JACS3555 ) Derivation of CC dihedral angles in a natural product-protein complex (03ANG2515)
H-H/H-C	Determination the relative orientation of a small allylpalladium complex ( 98ANG1903 ). Study of methyl relaxation in proteins ( 04JB369-29 )
H-N/N-CO	( 99JACS9165 )
H-N/H-N	(03JB265-25)