Structural Diversity of Amyloid Fibrils and Advances in Their Structure Determination

Protein amyloid fibrils are originally identified as pathological entities in a variety of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Recent studies have revealed that amyloid fibrils also serve as functional protein assemblies to fulfill a wide range of biological functions. Deciphering the molecular basis underlying the assembly of amyloid fibrils is essential for understanding their biological and pathological functions. Here, we summarize recent advances in the atomic structure determination of amyloid fibrils formed by both amyloidogenic peptides and full-length proteins. Furthermore, we demonstrate the diversity of amyloid fibrils, with a primary focus on the reversible fibrils, in sequence composition, self-assembled architecture, and physiochemical and pathological properties. Finally, we raise questions that will be answered by the future study of amyloid fibril structure.