The effect of side chains of amino acid residues in human calcitonin for fibrillation

Human calcitonin (HCT) is a thyroid polypeptide hormone that has 32 amino acid residues. The HCT is well known for an amyloid forming peptide and its inhibition of bone mineralization of calcium-phosphorous as osteoporosis. The HCT peptide aggregates to form insoluble fibril toward diseases. In the fibril formation of HCT, the local conformation changes from an α-helix in a monomeric HCT to a beta-sheet structure in a fibril. The role of the amino acid residues for fibrillation is unclear; therefore, we simulated to determine the interaction energies between amino acid residues for stability of fibril using molecular dynamics simulation.