The comparison of the structures of apo SOD1 dimer and SOD1 fibril reveals the substantial conformational conversion from a β-sheet-rich (correspond to the antiparallel β-barrel structure), immature form of SOD1 to a totally distinct β-sheet-rich (correspond to an in-register intramolecular β strand architecture), fibrillar form of SOD1 during pathogenesis of ALS. The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.