PROTEIN STRUCTURE ANALYSIS BASED ON RED-EDGE EXCITATION SHIFT (REES) SPECTROSCOPY

A protein structure analysis method is described that comprises : receiving a fluorescence emission spectrum generated by a protein sample at a first excitation wavelength, the protein sample being configured to exhibit fluorescence in dependence upon its conformational state; evaluating, from the fluorescence emission spectrum, an indication characteristic of a fluorescence response of the protein sample at the first excitation wavelength; repeating the receiving and evaluating steps in relation to a plurality of fluorescence emission spectra, each fluorescence spectrum generated by the protein sample at a different excitation wavelength to the first excitation wavelength; generating a non-linear relationship between excitation wavelength and indication characteristic of fluorescence response of the protein sample, the non-linear relationship comprising an indication of at least one characteristic of the conformational state of the protein sample, based upon correlation of the received excitation wavelengths and associated evaluated indications characteristic of the fluorescence response of the protein sample. The method can be used with any protein which includes one or more naturally occurring fluorescent amino acids (intrinsic fluorophores), and particularly those with Trp residues (most), or proteins having appropriately selected extrinsic fluorophores