NMR Derived Model of GTPase Effector Domain (GED) Self Association: Relevance to Dynamin Assembly

作者：Chakraborty Swagata; Pratihar Supriya; Hosur Ramakrishna V^*

来源：PLos One, 2012, 7(1): e30109.

DOI：10.1371/journal.pone.0030109

Self-association of dynamin to form spiral structures around lipidic vesicles during endocytosis is largely mediated by its %26apos;coiled coil%26apos; GTPase Effector Domain (GED), which, in vitro, self-associates into huge helical assemblies. Residue-level structural characterizations of these assemblies and understanding the process of association have remained a challenge. It is also impossible to get folded monomers in the solution phase. In this context, we have developed here a strategy to probe the self-association of GED by first dissociating the assembly using Dimethyl Sulfoxide (DMSO) and then systematically monitoring the refolding into helix and concomitant re-association using NMR spectroscopy, as DMSO concentration is progressively reduced. The short segment, Arg109 - Met116, acts as the nucleation site for helix formation and self-association. Hydrophobic and complementary charge interactions on the surfaces drive self-association, as the helices elongate in both the directions resulting in an antiparallel stack. A small N-terminal segment remains floppy in the assembly. Following these and other published results on inter-domain interactions, we have proposed a plausible mode of dynamin self assembly.

• 出版日期2012-1-12