NMR insights into a megadalton-size protein self-assembly.

Protein self-association is critical to many biological functions. However, atomic-level structural characterization of these assemblies has remained elusive. In this report we present insights into the mechanistic details of the process of self-association of the 136-residue GTPase effector domain (GED) of the endocytic protein dynamin into a megadalton-sized soluble mass. Our approach is based on NMR monitoring of regulated folding and association through Gdn-HCl titration. The results suggest the evolution of a sequence-self-association paradigm. Equally significantly, the study demonstrates an elegant bottom-up strategy that can render large protein self-assemblies accessible to NMR investigations that have remained difficult to date.