Proliferation of amyloid- 42 aggregates occurs through a secondary nucleation mechanism

Proliferation of amyloid-β42 aggregates occurs through a secondary nucleation mechanism.

The generation of toxic oligomers during the aggregation of the amyloid-β (Aβ) peptide Aβ42 into amyloid fibrils and plaques has emerged as a central feature of the onset and progression of Alzheimer's disease, but the molecular pathways that control pathological aggregation have proved challenging to identify. Here, we use a combination of kinetic studies, selective radiolabeling experiments, ...

Mechanism of Prion Propagation: Amyloid Growth Occurs by Monomer Addition

Abundant nonfibrillar oligomeric intermediates are a common feature of amyloid formation, and these oligomers, rather than the final fibers, have been suggested to be the toxic species in some amyloid diseases. Whether such oligomers are critical intermediates for fiber assembly or form in an alternate, potentially separable pathway, however, remains unclear. Here we study the polymerization of...

Secondary nucleation overcomes seeding template in amyloid-like fibril formation

Novel mechanistic insight into the molecular basis of amyloid polymorphism and secondary nucleation during amyloid formation.

The formation of amyloid β (Aβ) fibrils is crucial in initiating the cascade of pathological events that culminates in Alzheimer's disease. In this study, we investigated the mechanism of Aβ fibril formation from hydrodynamically well defined species under controlled aggregation conditions. We present a detailed mechanistic model that furnishes a novel insight into the process of Aβ42 fibril fo...

Nucleation of amyloid fibrils.

We consider nucleation of amyloid fibrils in the case when the process occurs by the mechanism of direct polymerization of practically fully extended protein segments, i.e., beta-strands, into beta-sheets. Applying the classical nucleation theory, we derive a general expression for the work to form a nanosized amyloid fibril (protofilament) constituted of successively layered beta-sheets. Analy...