title: 7 Å resolution in protein two-dimensional-crystal X-ray diffraction at Linac Coherent Light Source.
abstract: Membrane proteins arranged as two-dimensional crystals in the lipid environment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. Previously, X-ray diffraction from individual two-dimensional crystals did not represent a suitable investigational tool because of radiation damage. The recent availability of ultrashort pulses from X-ray free-electron lasers (XFELs) has now provided a means to outrun the damage. Here, we report on measurements performed at the Linac Coherent Light Source XFEL on bacteriorhodopsin two-dimensional crystals mounted on a solid support and kept at room temperature. By merging data from about a dozen single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 Å, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase in the resolution. The presented results pave the way for further XFEL studies on two-dimensional crystals, which may include pump-probe experiments at subpicosecond time resolution.
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland bill.pedrini@psi.ch.
authors.forename: Bill
authors.initials: B
authors.lastname: Pedrini
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Ching-Ju
authors.initials: CJ
authors.lastname: Tsai
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Guido
authors.initials: G
authors.lastname: Capitani
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Celestino
authors.initials: C
authors.lastname: Padeste
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Hunter
authors.affiliation: Department of Physics, Arizona State University, 300 E. University Drive, Tempe, AZ 85287, USA.
authors.forename: Nadia A
authors.initials: NA
authors.lastname: Zatsepin
authors.affiliation: Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Barty
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: W Henry
authors.initials: WH
authors.lastname: Benner
authors.affiliation: Linac Coherent Light Source, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutet
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Geoffrey K
authors.initials: GK
authors.lastname: Feld
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Hau-Riege
authors.affiliation: Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Kirian
authors.affiliation: Department of Physics, Arizona State University, 300 E. University Drive, Tempe, AZ 85287, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kupitz
authors.affiliation: Linac Coherent Light Source, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Messerschmitt
authors.affiliation: Physics Department, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA.
authors.forename: John I
authors.initials: JI
authors.lastname: Ogren
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Pardini
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Brent
authors.initials: B
authors.lastname: Segelke
authors.affiliation: Linac Coherent Light Source, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
authors.forename: Garth J
authors.initials: GJ
authors.lastname: Williams
authors.affiliation: Department of Physics, Arizona State University, 300 E. University Drive, Tempe, AZ 85287, USA.
authors.forename: John C H
authors.initials: JC
authors.lastname: Spence
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Rafael
authors.initials: R
authors.lastname: Abela
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Coleman
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Boulevard, Richland, WA 99354, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Evans
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Gebhard F X
authors.initials: GF
authors.lastname: Schertler
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA frank1@llnl.gov.
authors.forename: Matthias
authors.initials: M
authors.lastname: Frank
authors.affiliation: Paul Scherrer Institute, 5232 Villigen PSI, Switzerland xiao.li@psi.ch.
authors.forename: Xiao-Dan
authors.initials: XD
authors.lastname: Li
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000648:ultrastructure; D018360:Crystallography, X-Ray / Q000379:methods*; D004583:Electrons; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D011487:Protein Conformation; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D001436:Bacteriorhodopsins
keywords: X-ray diffraction; X-ray free-electron laser; bacteriorhodopsin; crystallographic data analysis; two-dimensional protein crystal