Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 41: Protein structure and dynamics I
BP 41.7: Vortrag
Donnerstag, 19. März 2015, 11:45–12:00, H 1058
Ultrafast Infrared Spectroscopy Reveals Water-mediated Coherent Dynamics in an Enzyme Active Site — •Katrin Adamczyk1, Niall Simpson1, Gregory M. Greetham2, Andrea Gumiero3, Martin A. Walsh3, Michael Towrie2, Anthony W. Parker2, and Neil T. Hunt1 — 1University of Strathclyde, Glasgow, UK — 2Central Laser Facility, Rutherford Appleton Laboratory, Didcot, UK — 3Diamond Light Source, Didcot, UK
Understanding the impact of fast dynamics upon chemical processes occurring within the active sites of proteins and enzymes is a key challenge that continues to attract interest. Similar gaps in our knowledge exist in understanding the role played by water, either as a solvent or as a structural/dynamic component of the active site. In order to investigate further the potential biological roles of water, ultrafast infrared spectroscopy is employed that directly probe the vibrational dynamics of NO bound to the ferric haem of the catalase enzyme from Corynebacterium glutamicum in both H2O and D2O. An isotope dependence of the vibrational relaxation parameters of the NO stretching vibration is observed indicating that water molecules interact directly with the haem ligand. Furthermore, IR pump-probe data feature quantum beats originating from the preparation of a coherent superposition of low-frequency vibrational modes in the active site of catalase that are coupled to the haem ligand stretching vibration. Together, the data establishes a strong interaction between the haem ligand and a water-mediated H-bond network in catalase that is likely to be pivotal to proton transfer events during the enzymatic cycle.