An infrared spectroscopic study of the conformational transition of elastin-like polypeptides.
The infrared spectroscopy of elastin-like polypeptides and the relation to the inverse thermal transition are discussed. To correlate the spectroscopic observations with structure a density function theory model was created that captures the essential hydrogen bonding and packing of the beta-spiral structure proposed for elastin and elastin-like polypeptides. The infrared spectrum was calculated using periodic boundary conditions and a method for estimating the difference dipole moment permits both frequencies and intensities to be obtained for the modeling of spectra. The two observed amide I bands at 1615 cm(-1) and 1656 cm(-1) are shown to arise from the beta-spiral structure. The increase in intensity of these bands with increasing salt concentration and temperature is assigned to the closer association of strands of the beta-spiral. The sharp inverse temperature transition is observed within 1 degrees C and involves a change in secondary structure that involves formation of interstrand beta-sheets for approximately 25% of the amino acids. This conclusion is consistent with available data and simulations that have been reported to date.
Serrano
Vesna
V
Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA.
Liu
Wenge
W
Franzen
Stefan
S
D003198:Computer Simulation; D004549:Elastin / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D016011:Normal Distribution; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012492:Salts / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D010455:Peptides; D012492:Salts; D012965:Sodium Chloride; D004549:Elastin