Amyloid formation of proteins is not only relevant for neurodegenerative diseases, but has recently emerged as a groundbreaking approach in material science and biotechnology. However, amyloid aggregation of proteins in vitro generally requires a long incubation time under extremely harsh conditions, and the understanding on structural motif to determine amyloid assembly is extremely lacking. Herein we reveal that the integration of three important building blocks in typical globular proteins is crucial for superfast protein amyloid-like assembly including the segment required for high fibrillation propensity, abundant α-helix structure and intramolecular S-S bond to lock the α-helix. With the reduction of the S-S bond by tris(2-carboxyethyl)phosphine (TCEP), the α-helix was rapidly unlocked from the protein chain, and the resultant unfolded monomer underwent a fast transition to β-sheet-rich amyloid oligomers and protofibrils in minutes, which further assembled into a macroscopic nanofilm at the air/water interface and microparticles in the bulk solution, respectively.