Two-dimensional infrared studies of biomolecules

Xabier Goto, Ibon Iloro and Jose Luis R. Arrondo 

Unidad de Biofisica (CSIC-UPV/EHU) and Departamento de Bioquimica, Universidad 

Chemical Biology Edited by Banafshe Larijani, Colin. A. Rosser and Rudiger Woscholski 2006 John Wiley Sons, Ltd 

More recently, Noda has proposed the use of infrared two-dimensional correlation spectroscopy (2D-IR) to increase the information that can be extracted from a spectrum. This approach, essentially different from 2D-NMR spectroscopy, uses correlation analysis of the dynamic fluctuations caused by an external perturbation to enhance spectral resolution without assuming any line shape model for the bands. The technique was intended for the study of polymers and liquid crystals, and it has recently been applied to proteins. In the latter case, the perturbation can be achieved through changes in temperature, pH, ligand concentration and lipid-to-protein ratio. 

Infrared spectroscopy can be used in turbid suspensions, such as membranes or with big proteins, but the methods for studying the spectrum are impaired by the difficult interpretation of the composite bands obtained from proteins. Thus, more powerful methods of spectral analysis are needed 

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