title: Methods development for diffraction and spectroscopy studies of metalloenzymes at X-ray free-electron lasers.
abstract: X-ray free-electron lasers (XFELs) open up new possibilities for X-ray crystallographic and spectroscopic studies of radiation-sensitive biological samples under close to physiological conditions. To facilitate these new X-ray sources, tailored experimental methods and data-processing protocols have to be developed. The highly radiation-sensitive photosystem II (PSII) protein complex is a prime target for XFEL experiments aiming to study the mechanism of light-induced water oxidation taking place at a Mn cluster in this complex. We developed a set of tools for the study of PSII at XFELs, including a new liquid jet based on electrofocusing, an energy dispersive von Hamos X-ray emission spectrometer for the hard X-ray range and a high-throughput soft X-ray spectrometer based on a reflection zone plate. While our immediate focus is on PSII, the methods we describe here are applicable to a wide range of metalloenzymes. These experimental developments were complemented by a new software suite, cctbx.xfel. This software suite allows for near-real-time monitoring of the experimental parameters and detector signals and the detailed analysis of the diffraction and spectroscopy data collected by us at the Linac Coherent Light Source, taking into account the specific characteristics of data measured at an XFEL.
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA jfkern@lbl.gov.
authors.forename: Jan
authors.initials: J
authors.lastname: Kern
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Johan
authors.initials: J
authors.lastname: Hattne
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Rosalie
authors.initials: R
authors.lastname: Tran
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Alonso-Mori
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Hartawan
authors.initials: H
authors.lastname: Laksmono
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Sheraz
authors.initials: S
authors.lastname: Gul
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Raymond G
authors.initials: RG
authors.lastname: Sierra
authors.affiliation: Institute for Nanometre Optics and Technology, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Rehanek
authors.affiliation: Institute for Nanometre Optics and Technology, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany.
authors.forename: Alexei
authors.initials: A
authors.lastname: Erko
authors.affiliation: Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Mitzner
authors.affiliation: Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 12489, Germany.
authors.forename: Phillip
authors.initials: P
authors.lastname: Wernet
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Uwe
authors.initials: U
authors.lastname: Bergmann
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Sauter
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Vittal
authors.initials: V
authors.lastname: Yachandra
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Junko
authors.initials: J
authors.lastname: Yano
mesh_terms: D004583:Electrons; D007834:Lasers; D017895:Manganese Compounds / Q000737:chemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D012984:Software; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D017895:Manganese Compounds; D045332:Photosystem II Protein Complex
keywords: X-ray crystallography; X-ray emission spectroscopy; X-ray free-electron laser; metalloenzymes; photosystem II; water oxidation