An oligomeric equilibrium intermediate as the precursory nucleus of globular and fibrillar supramacromolecular assemblies in a PDZ domain.

ABSTRACT: The equilibrium unfolding at neutral pH of the third PDZ domain of PSD95, as followed by DSC, is characterized by the presence of an equilibrium intermediate with clear signs of oligomerization. DLS and SEC measurements indicate that at 60-70 degrees C small oligomers populate, showing a typical beta-sheet far-UV CD spectrum. These intermediate species lead to the formation of rodlike particulates of approximately 12 nm, which remain in solution after 2 weeks incubation and grow until they adopt annular/spherical shapes of approximately 50 nm and protofibrils, which are subsequently fully transformed into fibrils. The fibrils can also disaggregate after the addition of 1:1 buffer dilution followed by cooling to room temperature, thus returning to the initial monomeric state. Growth kinetic

SUBMITTER: Murciano-Calles J 

PROVIDER: S-EPMC2895384 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature