Protein Backbone N Relaxation Rates as a Tool for the Diagnosis of Structure Quality

In the work reported herein we define a structure validation factor that depends on protein backbone ¹⁵N relaxation rates. This is an alternative method to the previously defined quality factors derived from anisotropic chemical shifts or residual dipolar couplings. We have used the structure dependence of ¹⁵N relaxation rates of anisotropically tumbling proteins to calculate this structure diagnosis factor and have used it to demonstrate the improvement of protein structures refined with residual dipolar couplings.