title: A novel BioXAS technique with sub-millisecond time resolution to track oxidation state and structural changes at biological metal centers.
abstract: Oxidation-state and structural changes at the metal center are crucial for the catalytic reactions of most metalloenzymes. The characterization of reaction intermediates is a prerequisite for understanding the catalytic mechanism. Frequently, intermediates are formed on the microsecond to millisecond timescale. To follow these reactions in real time represents a major challenge in structural biology. Time-resolved BioXAS is a particularly promising tool for resolving such intermediates. A novel approach for BioXAS, termed 'sampling-XAS', is presented. First room-temperature sampling-XAS results have been obtained for the manganese complex of oxygenic photosynthesis. Oxidation-state changes are monitored with a time resolution as good as 200 micros. The current prospects and limitations as well as future perspectives of time-resolved BioXAS are discussed.
authors.affiliation: Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany. haumann@physik.fu-berlin.de
authors.forename: Michael
authors.initials: M
authors.lastname: Haumann
authors.forename: Claudia
authors.initials: C
authors.lastname: Müller
authors.forename: Peter
authors.initials: P
authors.lastname: Liebisch
authors.forename: Thomas
authors.initials: T
authors.lastname: Neisius
authors.forename: Holger
authors.initials: H
authors.lastname: Dau
mesh_terms: D002384:Catalysis; D003198:Computer Simulation; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism; D008345:Manganese / Q000378:metabolism*; D008667:Metalloproteins; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D013057:Spectrum Analysis / Q000379:methods*; D014867:Water / Q000378:metabolism; D014965:X-Rays
chemical_list: D004798:Enzymes; D008667:Metalloproteins; D045322:Photosynthetic Reaction Center Complex Proteins; D014867:Water; D008345:Manganese