NMR Constraints

The paramagnetic pseudo-contact shift (PCS) occurs in molecules containing tighly bound rapidly relaxing paramagnetic metal ions such as lanthanides ( 00JACS4154 and 02EJIC2121 ) or certain transition metals such as iron and cobalt. Usually, two components can contribute to the paramagnetic shift, a scalar contact shift (through bond), which propagates about five to six bonds from the paramagnetic center, and a dipolar pseudocontact shift (through space).

  • Inclusion of paramagnetic shifts as constraints in structure determination ( 95PSC296-4 , 97BIO9867 , 97EJB721-244 , 98JB553-12 , 99JACS9276 , 00BIO5355 ). Use of the site-directed spin-labeling.
  • Examples of PCS on paramagnetic proteins:
  • Metalloprophyrins and metalloproteins ( 02JACS13911 and 02EJIC2121 )
  • Myoglobin ( 03CEJ2316 )
  • The use of chemical shift temperatures ( 00JB167 )
  • Measurement of dipolar couplings in paramagnetic proteins ( 98JACS12903 , 00JPCB2559; 00JB295, 00JB347 and 02JACS5581) to determine the magnetic susceptibility anisotropy.
  • Use of PCS and RDCs or other NMR restraints after introduction of a paramagnet binding site (04JB205-28 and 04JACS2963)
  • A comparative study of the paramagnetism-based constraints vs classical restraints in solution structure determinations of paramagnetic metalloproteins has been described. These constraints are presudocontacts shifts, residual dipolar couplings and nuclear relaxation enhancements. ( 01JB85-21 and 02JB123-22 )
  • Introduction of a paramagnetic probe to disrupt the symmetry of symmetric protein dimers ( 02JB143-24 ).
  • Relaxation:
  • Cross-correlated relaxation between the nuclear spin and the electron spin involving HN dipolar couplings and Curie spin relaxation (CSR) ( 01JB31-20 , 01JMR103-152 , 99JACS7700 , 02JB115-23 and 03JB115-27 ).
  • Study of paramagnetic longitudinal (R1) relaxation ( 00JACS9473 , 00JACS7823 , 03JACS6858 , 02JACS4093 and 04JB175-29 ) and transverse (R2) relaxation ( 01JACS9843 )
  • Determination of electron self-exchange rates ( 01JB199 and 02JACS4093 ).Strategy for the study of paramagnetic proteins with slow electronic relaxation rates ( 04JACS5426 )
  • Relaxation in dimers ( 98ACR351 )
  • Incorporation of NMR restraints in Xplor-NIH ( 04JB249 )