title: Thermal stability and conformational structure of salmon calcitonin in the solid and liquid states.
abstract: Salmon calcitonin (sCT) was selected as a model protein drug for investigating its intrinsic thermal stability and conformational structure in the solid and liquid states by using a Fourier transform infrared (FT-IR) microspectroscopy with or without utilizing thermal analyzer. The spectral correlation coefficient (r) analysis between two second-derivative IR spectra was applied to quantitatively estimate the structural similarity of sCT in the solid state before and after different treatments. The thermal FT-IR microspectroscopic data clearly evidenced that sCT in the solid state was not effected by temperature and had a thermal reversible property during heating-cooling process. Moreover, the high r value of 0.973 or 0.988 also evidenced the structural similarity of solid-state sCT samples before and after treatments. However, sCT in H(2)O exhibited protein instability and thermal irreversibility after incubation at 40 degrees C. The temperature-induced conformational changes of sCT in H(2)O was occurred to transform the alpha-helix/random coil structures to beta-sheet structure and also resulted in the formation of intramolecular and intermolecular beta-sheet structures.
authors.affiliation: Department of Biotechnology, Yuanpei University, Hsin Chu, Taiwan, Republic of China.
authors.forename: Ting-Huei
authors.initials: TH
authors.lastname: Lee
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Cheng
authors.forename: Shan-Yang
authors.initials: SY
authors.lastname: Lin
mesh_terms: D000818:Animals; D002116:Calcitonin / Q000737:chemistry*; D011487:Protein Conformation; D055550:Protein Stability; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D012996:Solutions; C028815:salmon calcitonin; D002116:Calcitonin