title: Terahertz underdamped vibrational motion governs protein-ligand binding in solution.
abstract: Low-frequency collective vibrational modes in proteins have been proposed as being responsible for efficiently directing biochemical reactions and biological energy transport. However, evidence of the existence of delocalized vibrational modes is scarce and proof of their involvement in biological function absent. Here we apply extremely sensitive femtosecond optical Kerr-effect spectroscopy to study the depolarized Raman spectra of lysozyme and its complex with the inhibitor triacetylchitotriose in solution. Underdamped delocalized vibrational modes in the terahertz frequency domain are identified and shown to blue-shift and strengthen upon inhibitor binding. This demonstrates that the ligand-binding coordinate in proteins is underdamped and not simply solvent-controlled as previously assumed. The presence of such underdamped delocalized modes in proteins may have significant implications for the understanding of the efficiency of ligand binding and protein-molecule interactions, and has wider implications for biochemical reactivity and biological function.
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: Turton
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow, UK.
authors.forename: Hans Martin
authors.initials: HM
authors.lastname: Senn
authors.affiliation: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Harwood
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow, UK.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Lapthorn
authors.affiliation: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Ellis
authors.affiliation: School of Chemistry, WestCHEM, University of Glasgow, Glasgow, UK.
authors.forename: Klaas
authors.initials: K
authors.lastname: Wynne
mesh_terms: D000818:Animals; D002645:Chickens; D009113:Muramidase / Q000378:metabolism*; D011485:Protein Binding; D013059:Spectrum Analysis, Raman; D014312:Trisaccharides / Q000378:metabolism*; D014732:Vibration
chemical_list: D014312:Trisaccharides; C019117:N,N',N''-triacetylchitotriose; D009113:Muramidase