Vibrational spectroscopy for quantitative measurement of analytes

摘要

The present invention relates to systems and methods for the determination of the secondary structure composition of proteins using coherent two-dimensional infrared (2DIR) spectroscopy of backbone amide I vibrations (1580-1720 cm⁻¹). Fractions of α-helix, β-sheet, and unassigned regions in globular proteins were determined by singular value decomposition using basis spectra from sixteen commercially-available proteins with known crystal structures. Preferred methods included removing each protein from the set and comparing the predicted composition against the crystal structure. The root-mean-squared (RMS) errors of the predicted secondary structure compositions were found to be 7.9% for α-helix, 5.5% for β-sheet, and 7.6% for unassigned regions. The structure analysis can also be performed using one-dimensional absorption spectra and the RMS errors are compared with those obtained from 2DIR.