title: De novo protein crystal structure determination from X-ray free-electron laser data.
abstract: The determination of protein crystal structures is hampered by the need for macroscopic crystals. X-ray free-electron lasers (FELs) provide extremely intense pulses of femtosecond duration, which allow data collection from nanometre- to micrometre-sized crystals in a 'diffraction-before-destruction' approach. So far, all protein structure determinations carried out using FELs have been based on previous knowledge of related, known structures. Here we show that X-ray FEL data can be used for de novo protein structure determination, that is, without previous knowledge about the structure. Using the emerging technique of serial femtosecond crystallography, we performed single-wavelength anomalous scattering measurements on microcrystals of the well-established model system lysozyme, in complex with a lanthanide compound. Using Monte-Carlo integration, we obtained high-quality diffraction intensities from which experimental phases could be determined, resulting in an experimental electron density map good enough for automated building of the protein structure. This demonstrates the feasibility of determining novel protein structures using FELs. We anticipate that serial femtosecond crystallography will become an important tool for the structure determination of proteins that are difficult to crystallize, such as membrane proteins.
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Thomas R M
authors.initials: TR
authors.lastname: Barends
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Foucar
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Botha
authors.affiliation: 1] Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany [2] Department of Physics, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, USA.
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Doak
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Shoeman
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Karol
authors.initials: K
authors.lastname: Nass
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Koglin
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Garth J
authors.initials: GJ
authors.lastname: Williams
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutet
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Messerschmidt
authors.affiliation: Max-Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Ilme
authors.initials: I
authors.lastname: Schlichting
mesh_terms: D000818:Animals; D002645:Chickens; D003460:Crystallization; D003461:Crystallography / Q000379:methods*; D004583:Electrons; D005260:Female; D005682:Gadolinium; D007834:Lasers; D008565:Membrane Proteins / Q000737:chemistry; D008958:Models, Molecular; D009010:Monte Carlo Method; D009113:Muramidase / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D013997:Time Factors; D014961:X-Ray Diffraction / Q000379:methods*; D014965:X-Rays
chemical_list: D008565:Membrane Proteins; D011506:Proteins; D005682:Gadolinium; C421864:hen egg lysozyme; D009113:Muramidase