Determining beta-sheet stability by Fourier transform infrared difference spectra.
We describe here a new method for determining the conformational stability of antiparallel beta-sheets. Due to coupling between the transition dipoles, beta-sheet conformations typically exhibit a characteristic high-frequency amide I component centered at approximately 1680 cm(-1). Using one beta-sheet protein and two small beta-hairpins, we demonstrate that this high-frequency component, which is fairly narrow (approximately 8-10 cm(-1)), can be quantitatively resolved and used in thermal stability determination. Compared with the commonly used CD and fluorescence techniques, this ir method offers advantages. Since the area of this high-frequency component is only proportional to the folded population, it eliminates the need for a priori information of the folded and unfolded baselines encountered in other methods. Thus, it is applicable to a variety of beta-sheet systems.
Wang
Ting
T
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
Xu
Yao
Y
Du
Deguo
D
Gai
Feng
F
D009682:Magnetic Resonance Spectroscopy; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D011506:Proteins