Experimental characterization of models for backbone picosecond dynamics in proteins. Quantification of NMR auto- and cross-correlation relaxation mechanisms involving different nuclei of the peptide plane

There is a poor correlation between the general order NMR relaxation parameters of the C'-C-alpha vector in the peptide-plane carbonyl and nitrogen nuclei of the protein Escherichia coli flavodoxin. This can be regarded as evidence of local or semilocal anisotropic motion. It is important to measure relaxation parameters of several vectors in a motional unit to describe its dynamic properties. Daragan and Mayo's motional modeling is a good description of the consequences of anisotropic motion in a module that is geometrically linked.