Temperature-induced conformational changes in amyloid beta(1-40) peptide investigated by simultaneous FT-IR microspectroscopy with thermal system.
Temperature-dependent secondary structures of the amyloid beta(1-40) peptide in the solid state were studied by simultaneous Fourier transform infrared/differential scanning calorimetry (FT-IR/DSC) microspectroscopic system with the heating-cooling-reheating cycle. The result indicates that a thermal transition temperature at 45 degrees C was easily obtained from the three-dimensional plot of the transmission FT-IR spectra as a function of temperature. Furthermore, the thermal-dependent conformational transformations, due to denaturation and aggregation, of solid amyloid beta(1-40) were mainly evidenced by reducing the compositions from 37 to 20-24% for alpha-helical and random coil structures but increasing the components from 27 to 45% for intermolecular beta-sheet structures. Thermal-irreversible behavior and a poor thermal stability of solid amyloid beta(1-40) were also observed from the poor restoration of the secondary conformational changes in the heated sample.
Chu
H L
HL
Department of Medical Research and Education, Veterans General Hospital-Taipei, Taiwan.
Lin
S Y
SY
D000544:Alzheimer Disease / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D006801:Humans; D010446:Peptide Fragments / Q000737:chemistry*; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40)