Structural analysis of proinsulin hexamer assembly by hydroxyl radical footprinting and computational modeling.

ABSTRACT: Mutations in the insulin gene can impair proinsulin folding and cause diabetes mellitus. Although crystal structures of insulin dimers and hexamers are well established, proinsulin is refractory to crystallization. Although an NMR structure of an engineered proinsulin monomer has been reported, structures of the wild-type monomer and hexamer remain undetermined. We have utilized hydroxyl radical footprinting and molecular modeling to characterize these structures. Differences between the footprints of insulin and proinsulin, defining a "shadow" of the connecting (C) domain, were employed to refine the model. Our results demonstrate that in its monomeric form, (i) proinsulin contains a native-like insulin moiety and (ii) the C-domain footprint resides within an adjoining segment (residues B

SUBMITTER: Kiselar JG 

PROVIDER: S-EPMC3243561 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature