title: Ultrafast Structural Fluctuations of Myoglobin-Bound Thiocyanate and Selenocyanate Ions Measured with Two-Dimensional Infrared Photon Echo Spectroscopy.
abstract: Structural dynamics within the distal cavity of myoglobin protein is investigated using 2D-IR and IR pump-probe spectroscopy of the N≡C stretch modes of heme-bound thiocyanate and selenocyanate ions. Although myoglobin-bound thiocyanate group shows a doublet in its IR absorption spectrum, no cross peaks originating from chemical exchange between the two components are observed in the time-resolved 2D IR spectra within the experimental time window. Frequency-frequency correlation functions of the two studied anionic ligands are obtained by means of a few different analysis approaches; these functions were then used to elucidate the differences in structural fluctuation around ligand, ligand-protein interactions, and the degree of structural heterogeneity within the hydrophobic pocket of these myoglobin complexes.
authors.affiliation: Korea University, Chemistry, 145 Anam-ro, Seongbuk-gu, Seoul, 136-701, Republic of Korea.
authors.forename: Michał
authors.identifier: http://orcid.org/0000-0003-1567-9514
authors.initials: M
authors.lastname: Maj
authors.affiliation: Korea University, Chemistry, 145 Anam-ro, Seongbuk-gu, Seoul, 136-701, Republic of Korea.
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Kwak
authors.affiliation: Korea University, Chemistry, 145 Anam-ro, Seongbuk-gu, Seoul, 136-701, Republic of Korea. mcho@korea.ac.kr.
authors.forename: Minhaeng
authors.identifier: http://orcid.org/0000-0003-1618-1056
authors.initials: M
authors.lastname: Cho
mesh_terms: D000818:Animals; D003485:Cyanates / Q000737:chemistry* / Q000378:metabolism; D006736:Horses; D007477:Ions / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism; D018036:Selenium Compounds / Q000737:chemistry* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013861:Thiocyanates / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003485:Cyanates; D007477:Ions; D009211:Myoglobin; D018036:Selenium Compounds; D013861:Thiocyanates; C018013:carboxymyoglobin; C031560:myoglobin nitroxide; C053721:selenocyanic acid; C031760:thiocyanate
keywords: IR spectroscopy; myoglobin; protein dynamics; ultrafast vibrational dynamics; vibrational spectroscopy