title: NMR derived model of GTPase effector domain (GED) self association: relevance to dynamin assembly.
abstract: Self-association of dynamin to form spiral structures around lipidic vesicles during endocytosis is largely mediated by its 'coiled coil' 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.
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India.
authors.forename: Swagata
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Supriya
authors.initials: S
authors.lastname: Pratihar
authors.forename: Ramakrishna V
authors.initials: RV
authors.lastname: Hosur
mesh_terms: D004121:Dimethyl Sulfoxide; D034281:Dynamins / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009038:Motion; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D034281:Dynamins; D004121:Dimethyl Sulfoxide