Protein backbone motions viewed by intraresidue and sequential HN-Halpha residual dipolar couplings.

ABSTRACT: Triple resonance E.COSY-based techniques were used to measure intra-residue and sequential H(N)-H(alpha) residual dipolar couplings (RDCs) for the third IgG-binding domain of protein G (GB3), aligned in Pf1 medium. Measurements closely correlate with values predicted on the basis of an NMR structure, previously determined on the basis of a large number of one-bond backbone RDCs measured in five alignment media. However, in particular the sequential H(N)-H(alpha) RDCs are smaller than predicted for a static structure, suggesting a degree of motion for these internuclear vectors that exceeds that of the backbone amide N-H vectors. Of all experimentally determined GB3 structures available, the best correlation between experimental (1)H-(1)H couplings is observed for a GB3 ensemble, previously

SUBMITTER: Vogeli B 

PROVIDER: S-EPMC2587141 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature