Amyloid fold (Amyloid)

The amyloid fold is a distinctive protein quaternary structure characterized by a cross-beta sheet motif, where individual beta-strands are oriented perpendicular to the long axis of the fibril. This structural arrangement is the defining feature of amyloidosis, a broad category of diseases where normally soluble proteins misfold and assemble into insoluble, toxic fibers that accumulate in tissues and organs. While many different proteins (such as amyloid-beta, tau, alpha-synuclein, and transthyretin) can form this fold, the resulting fibrils share similar biophysical properties and staining characteristics, such as apple-green birefringence under polarized light when stained with Congo Red. Therapeutic strategies targeting the amyloid fold include monoclonal antibodies designed to recognize and clear aggregated species, small molecules that stabilize the native state of proteins to prevent misfolding, and inhibitors that disrupt the nucleation or growth of the fibrils. The amyloid fold serves as a critical target for both disease-modifying therapies and diagnostic imaging agents in neurodegenerative and systemic diseases.

Other names

Cross-beta structureAmyloid fibrilBeta-amyloid foldAmyloidogenic protein foldMisfolded protein aggregate

Amyloid clearance via immunotherapy, kinetic stabilization of native protein precursors, inhibition of fibril elongation, and disaggregation of existing fibrils.