Measuring protein elasticity with terahertz spectroscopy

Elasticity is a key parameter in evaluating the structural stability of large polymeric molecules such as polysaccharides and polypeptides. The determination of the elastic parameters of complex biomolecules has been a long-standing challenge and terahertz spectroscopy is emerging as an ideal approach for such measurements. A new methodology is presented here, combining time-domain terahertz spectroscopy, X-ray diffraction, and solid-state density functional theory to achieve high-accuracy values for the Young's moduli of biopolymers. The capabilities are demonstrated by application of this method to crystalline poly-L-proline helices and other polypeptides.