title: An isomorphous replacement method for efficient de novo phasing for serial femtosecond crystallography.
abstract: Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) holds great potential for structure determination of challenging proteins that are not amenable to producing large well diffracting crystals. Efficient de novo phasing methods are highly demanding and as such most SFX structures have been determined by molecular replacement methods. Here we employed single isomorphous replacement with anomalous scattering (SIRAS) for phasing and demonstrate successful application to SFX de novo phasing. Only about 20,000 patterns in total were needed for SIRAS phasing while single wavelength anomalous dispersion (SAD) phasing was unsuccessful with more than 80,000 patterns of derivative crystals. We employed high energy X-rays from SACLA (12.6 keV) to take advantage of the large anomalous enhancement near the LIII absorption edge of Hg, which is one of the most widely used heavy atoms for phasing in conventional protein crystallography. Hard XFEL is of benefit for de novo phasing in the use of routinely used heavy atoms and high resolution data collection.
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Dongqing
authors.initials: D
authors.lastname: Pan
authors.affiliation: Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Okuda
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Sugahara
authors.affiliation: Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kodan
authors.affiliation: Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Murai
authors.affiliation: Research and Development Division, Kikkoman Corporation, Noda, 278-0037, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Gomi
authors.affiliation: Research and Development Division, Kikkoman Corporation, Noda, 278-0037, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kajiyama
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Mizohata
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.|Research Center for Structural and Functional Proteomics, Institute for Protein Research, Osaka University, Suita, 565-0871, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Nango
authors.affiliation: Japan Synchrotron Radiation Research Institute, Sayo, 679-5148, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Tono
authors.affiliation: Japan Synchrotron Radiation Research Institute, Sayo, 679-5148, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Joti
authors.affiliation: Japan Synchrotron Radiation Research Institute, Sayo, 679-5148, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kameshima
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Jaehyun
authors.initials: J
authors.lastname: Park
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Changyong
authors.initials: C
authors.lastname: Song
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Takaki
authors.initials: T
authors.lastname: Hatsui
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Makina
authors.initials: M
authors.lastname: Yabashi
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.|Department of Cell Biology, Graduate School of Medicine, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Iwata
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.|Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kato
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ago
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: RIKEN SPring-8 Center, Sayo, 679-5148, Japan.|Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, 606-8501, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakatsu
mesh_terms: D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins