Isotope-Labeled Aspartate Sidechain as a Non-Perturbing Infrared Probe: Application to Investigate the Dynamics of a Carboxylate Buried Inside a Protein.
Chem Phys Lett 2017 Sep 23;683:193-198. Epub 2017 Mar 23.
Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, PA 19104, USA.
Because of their negatively charged carboxylates, aspartate and glutamate are frequently found at the active or binding site of proteins. However, studying a specific carboxylate in proteins that contain multiple aspartates and/or glutamates via infrared spectroscopy is difficult due to spectral overlap. We show, herein, that isotopic-labeling of the aspartate sidechain can overcome this limitation as the resultant (13)C=O asymmetric stretching vibration resides in a transparent region of the protein IR spectrum. Read More