title: Krypton Derivatization of an O2 -Tolerant Membrane-Bound [NiFe] Hydrogenase Reveals a Hydrophobic Tunnel Network for Gas Transport.
abstract: [NiFe] hydrogenases are metalloenzymes catalyzing the reversible heterolytic cleavage of hydrogen into protons and electrons. Gas tunnels make the deeply buried active site accessible to substrates and inhibitors. Understanding the architecture and function of the tunnels is pivotal to modulating the feature of O2 tolerance in a subgroup of these [NiFe] hydrogenases, as they are interesting for developments in renewable energy technologies. Here we describe the crystal structure of the O2 -tolerant membrane-bound [NiFe] hydrogenase of Ralstonia eutropha (ReMBH), using krypton-pressurized crystals. The positions of the krypton atoms allow a comprehensive description of the tunnel network within the enzyme. A detailed overview of tunnel sizes, lengths, and routes is presented from tunnel calculations. A comparison of the ReMBH tunnel characteristics with crystal structures of other O2 -tolerant and O2 -sensitive [NiFe] hydrogenases revealed considerable differences in tunnel size and quantity between the two groups, which might be related to the striking feature of O2 tolerance.
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Kalms
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Schmidt
authors.affiliation: Institut für Chemie, Sekr. PC14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Stefan
authors.identifier: 0000-0002-4141-7836
authors.initials: S
authors.lastname: Frielingsdorf
authors.affiliation: ESRF-European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble Cedex 9, 38043, France.
authors.forename: Peter
authors.identifier: 0000-0002-3481-0787
authors.initials: P
authors.lastname: van der Linden
authors.affiliation: ESRF-European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble Cedex 9, 38043, France.
authors.forename: David
authors.initials: D
authors.lastname: von Stetten
authors.affiliation: Institut für Chemie, Sekr. PC14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Oliver
authors.identifier: 0000-0003-4550-5128
authors.initials: O
authors.lastname: Lenz
authors.affiliation: ESRF-European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble Cedex 9, 38043, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Carpentier
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. patrick.scheerer@charite.de.
authors.forename: Patrick
authors.identifier: 0000-0001-5028-2075
authors.initials: P
authors.lastname: Scheerer
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D020118:Cupriavidus necator / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D011487:Protein Conformation
chemical_list: C043296:nickel-iron hydrogenase; D006864:Hydrogenase; D010100:Oxygen
keywords: hydrogenases; krypton; metalloenzymes; oxygen; structural biology