J. Phys. Chem. B 2010, 114, 17187–17193
17187
Conformational Switching between Protein Substates Studied with 2D IR Vibrational Echo Spectroscopy and Molecular Dynamics Simulations Sayan Bagchi,†,⊥ Dayton G. Thorpe,‡,§,⊥ Ian F. Thorpe,‡,| Gregory A. Voth,*,‡ and M. D. Fayer*,† Department of Chemistry, Stanford UniVersity, Stanford, California 94305, United States, and Department of Chemistry, James Franck Institute, and Computation Institute, UniVersity of Chicago, 5735 South Ellis AVenue, Chicago, Illinois 60637, United States ReceiVed: September 26, 2010; ReVised Manuscript ReceiVed: October 27, 2010
Myoglobin is an important protein for the study of structure and dynamics. Three conformational substates have been identified for the carbonmonoxy form of myoglobin (MbCO). These are manifested as distinct peaks in the IR absorption spectrum of the CO stretching mode. Ultrafast 2D IR vibrational echo chemical exchange experiments are used to observed switching between two of these substates, A1 and A3, on a time scale of
