| 1. |
- Vinko, S. M., et al.
(författare)
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Electronic Structure of an XUV Photogenerated Solid-Density Aluminum Plasma
- 2010
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 104:22, s. 225001-
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Tidskriftsartikel (refereegranskat)abstract
- By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.
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| 2. |
- Echelmeier, A., et al.
(författare)
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Segmented flow generator for serial crystallography at the European X-ray free electron laser
- 2020
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported.
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| 3. |
- Pedersoli, E., et al.
(författare)
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Mesoscale morphology of airborne core-shell nanoparticle clusters : x-ray laser coherent diffraction imaging
- 2013
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16 SI, s. 164033-
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Tidskriftsartikel (refereegranskat)abstract
- Unraveling the complex morphology of functional materials like core-shell nanoparticles and its evolution in different environments is still a challenge. Only recently has the single-particle coherent diffraction imaging (CDI), enabled by the ultrabright femtosecond free-electron laser pulses, provided breakthroughs in understanding mesoscopic morphology of nanoparticulate matter. Here, we report the first CDI results for Co@SiO2 core-shell nanoparticles randomly clustered in large airborne aggregates, obtained using the x-ray free-electron laser at the Linac Coherent Light Source. Our experimental results compare favourably with simulated diffraction patterns for clustered Co@SiO2 nanoparticles with similar to 10 nm core diameter and similar to 30 nm shell outer diameter, which confirms the ability to resolve the mesoscale morphology of complex metastable structures. The findings in this first morphological study of core-shell nanomaterials are a solid base for future time-resolved studies of dynamic phenomena in complex nanoparticulate matter using x-ray lasers.
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| 4. |
- Duane Loh, N., et al.
(författare)
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Profiling structured beams using injected aerosols
- 2012
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Ingår i: Proceedings of SPIE. - : SPIE. - 9780819492210 ; , s. 850403-
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Konferensbidrag (refereegranskat)abstract
- Profiling structured beams produced by X-ray free-electron lasers (FELs) is crucial to both maximizing signal intensity for weakly scattering targets and interpreting their scattering patterns. Earlier ablative imprint studies describe how to infer the X-ray beam profile from the damage that an attenuated beam inflicts on a substrate. However, the beams in-situ profile is not directly accessible with imprint studies because the damage profile could be different from the actual beam profile. On the other hand, although a Shack-Hartmann sensor is capable of in-situ profiling, its lenses may be quickly damaged at the intense focus of hard X-ray FEL beams. We describe a new approach that probes the in-situ morphology of the intense FEL focus. By studying the translations in diffraction patterns from an ensemble of randomly injected sub-micron latex spheres, we were able to determine the non-Gaussian nature of the intense FEL beam at the Linac Coherent Light Source (SLAC National Laboratory) near the FEL focus. We discuss an experimental application of such a beam-profiling technique, and the limitations we need to overcome before it can be widely applied.
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| 5. |
- Vinko, S. M., et al.
(författare)
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Time-Resolved XUV Opacity Measurements of Warm Dense Aluminum
- 2020
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Ingår i: Physical Review Letters. - : American Physical Society. - 1079-7114 .- 0031-9007. ; 124:22
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Tidskriftsartikel (refereegranskat)abstract
- The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order of the Fermi energy. Plasma heating and opacity enhancement are observed on ultrafast timescales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm dense matter.
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| 6. |
- Chapman, H N, et al.
(författare)
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Coherent imaging at FLASH
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 186:1, s. 012051-
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Tidskriftsartikel (refereegranskat)abstract
- We have carried out high-resolution single-pulse coherent diffractive imaging at the FLASH free-electron laser. The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of an object before that object turns into a plasma and explodes. In particular we are developing imaging of biological specimens beyond conventional radiation damage resolution limits, developing imaging of ultrafast processes, and testing methods to characterize and perform single-particle imaging.
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| 7. |
- Hajkova, V., et al.
(författare)
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X-ray laser-induced ablation of lead compounds
- 2011
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Ingår i: DAMAGE TO VUV, EUV, AND X-RAY OPTICS III. - : SPIE.
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Konferensbidrag (refereegranskat)abstract
- The recent commissioning of a X-ray free-electron laser triggered an extensive research in the area of X-ray ablation of high-Z, high-density materials. Such compounds should be used to shorten an effective attenuation length for obtaining clean ablation imprints required for the focused beam analysis. Compounds of lead (Z=82) represent the materials of first choice. In this contribution, single-shot ablation thresholds are reported for PbWO(4) and PbI(2) exposed to ultra-short pulses of extreme ultraviolet radiation and X-rays at FLASH and LCLS facilities, respectively. Interestingly, the threshold reaches only 0.11 J/cm(2) at 1.55 nm in lead tungstate although a value of 0.4 J/cm(2) is expected according to the wavelength dependence of an attenuation length and the threshold value determined in the XUV spectral region, i.e., 79 mJ/cm(2) at a FEL wavelength of 13.5 nm. Mechanisms of ablation processes are discussed to explain this discrepancy. Lead iodide shows at 1.55 nm significantly lower ablation threshold than tungstate although an attenuation length of the radiation is in both materials quite the same. Lower thermal and radiation stability of PbI(2) is responsible for this finding.
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| 8. |
- Loh, N. D., et al.
(författare)
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Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight
- 2012
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 486:7404, s. 513-517
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of micrometre-size particulate matter is of critical importance in fields ranging from toxicology(1) to climate science(2), yet these properties are surprisingly difficult to measure in the particles' native environment. Electron microscopy requires collection of particles on a substrate(3); visible light scattering provides insufficient resolution(4); and X-ray synchrotron studies have been limited to ensembles of particles(5). Here we demonstrate an in situ method for imaging individual sub-micrometre particles to nanometre resolution in their native environment, using intense, coherent X-ray pulses from the Linac Coherent Light Source(6) free-electron laser. We introduced individual aerosol particles into the pulsed X-ray beam, which is sufficiently intense that diffraction from individual particles can be measured for morphological analysis. At the same time, ion fragments ejected from the beam were analysed using mass spectrometry, to determine the composition of single aerosol particles. Our results show the extent of internal dilation symmetry of individual soot particles subject to non-equilibrium aggregation, and the surprisingly large variability in their fractal dimensions. More broadly, our methods can be extended to resolve both static and dynamic morphology of general ensembles of disordered particles. Such general morphology has implications in topics such as solvent accessibilities in proteins(7), vibrational energy transfer by the hydrodynamic interaction of amino acids(8), and large-scale production of nanoscale structures by flame synthesis(9).
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| 9. |
- Bogan, M. J., et al.
(författare)
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Single-shot femtosecond x-ray diffraction from randomly oriented ellipsoidal nanoparticles
- 2010
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Ingår i: Physical Review Special Topics - Accelerators and Beams. - 1098-4402. ; 13:9, s. 094701-
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Tidskriftsartikel (refereegranskat)abstract
- Coherent diffractive imaging of single particles using the single-shot "diffract and destroy" approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250 nm x 50 nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle's orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.
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| 10. |
- Hau-Riege, S. P., et al.
(författare)
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Force Field Benchmark of Organic Liquids : Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:14, s. 145502-
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Tidskriftsartikel (refereegranskat)abstract
- At the recently built FLASH x-ray free-electron laser, we studied the reflectivity of Si/C multilayers with fluxes up to 3×1014W/cm2. Even though the nanostructures were ultimately completely destroyed, we found that they maintained their integrity and reflectance characteristics during the 25-fs-long pulse, with no evidence for any structural changes over lengths greater than 3Å. This experiment demonstrates that with intense ultrafast pulses, structural damage does not occur during the pulse, giving credence to the concept of diffraction imaging of single macromolecules.
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| 11. |
- Hau-Riege, S. P., et al.
(författare)
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Wavelength dependence of the damage threshold of inorganic materials under extreme-ultraviolet free-electron-laser irradiation
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 95:11, s. 111104-111104-3
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Tidskriftsartikel (refereegranskat)abstract
- We exposed bulk SiC and films of SiC and B4C to single 25 fs long free-electron-laser pulses with wavelengths between 13.5 and 32 nm. The materials are candidates for x-ray free-electron laser optics. We found that the threshold for surface-damage of the bulk SiC samples exceeds the fluence required for thermal melting at all wavelengths. The damage threshold of the film sample shows a strong wavelength dependence. For wavelengths of 13.5 and 21.7 nm, the damage threshold is equal to or exceeds the melting threshold, whereas at 32 nm the damage threshold falls below the melting threshold.
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| 12. |
- Iwan, Bianca S, et al.
(författare)
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TOF-OFF : A method for determining focal positions in tightly focused free-electron laser experiments by measurement of ejected ions
- 2011
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Ingår i: High Energy Density Physics. - : Elsevier BV. - 1574-1818. ; 7:4, s. 336-342
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Tidskriftsartikel (refereegranskat)abstract
- Pulse intensities greater than 1017 Watt/cm2 were reached at the FLASH soft X-ray laser in Hamburg, Germany, using an off-axis parabolic mirror to focus 15 fs pulses of 5–70 μJ energy at 13.5 nm wavelength to a micron-sized spot. We describe the interaction of such pulses with niobium and vanadium targets and their deuterides. The beam produced craters in the solid targets, and we measured the kinetic energy of ions ejected from these craters. Ions with several keV kinetic energy were observed from craters approaching 5 μm in depth when the sample was at best focus. We also observed the onset of saturation in both ion acceleration and ablation with pulse intensities exceeding 1016 W/cm2, when the highest detected ion energies and the crater depths tend to saturate with increasing intensity. A general difficulty in working with micron and sub-micron focusing optics is finding the exact focus of the beam inside a vacuum chamber. Here we propose a direct method to measure the focal position to a resolution better than the Rayleigh length. The method is based on the correlation between the energies of ejected ions and the physical dimensions of the craters. We find that the focus position can be quickly determined from the ion time-of-flight (TOF) data as the target is scanned through the expected focal region. The method does not require external access to the sample or venting the vacuum chamber. Profile fitting employed to analyze the TOF data can extend resolution beyond the actual scanning step size.
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| 13. |
- Lechner, C., et al.
(författare)
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First direct seeding at 38 nm
- 2012
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Ingår i: FEL 2012 - 34th International Free Electron Laser Conference. - 9783954501236 ; , s. 197-199
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The sFLASH project at DESY is an experiment to study direct seeding using a source based on the high-harmonic generation (HHG) process. In contrast to SASE, a seeded FEL exhibits greatly improved longitudinal coherence and higher shot-to-shot stability (both spectral and energetic). In addition, the output of the seeded FEL is intrinsically synchronized to the HHG drive laser, thus enabling pump-probe experiments with a resolution of the order of 10 fs. The installation and successful commissioning of the sFLASH components in 2010/2011 has been followed by a planned upgrade in autumn 2011. As a result of these improvements, in spring 2012 direct HHG seeding at 38 nm has been successfully demonstrated. In this contribution, we describe the experimental layout and announce the first seeding at 38 nm.
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| 14. |
- Martin, A. V., et al.
(författare)
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Femtosecond dark-field imaging with an X-ray free electron laser
- 2012
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Ingår i: Optics Express. - 1094-4087. ; 20:12, s. 13501-13512
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of femtosecond diffractive imaging with X-ray lasers has enabled pioneering structural studies of isolated particles, such as viruses, at nanometer length scales. However, the issue of missing low frequency data significantly limits the potential of X-ray lasers to reveal sub-nanometer details of micrometer-sized samples. We have developed a new technique of dark-field coherent diffractive imaging to simultaneously overcome the missing data issue and enable us to harness the unique contrast mechanisms available in dark-field microscopy. Images of airborne particulate matter (soot) up to two microns in length were obtained using single-shot diffraction patterns obtained at the Linac Coherent Light Source, four times the size of objects previously imaged in similar experiments. This technique opens the door to femtosecond diffractive imaging of a wide range of micrometer-sized materials that exhibit irreproducible complexity down to the nanoscale, including airborne particulate matter, small cells, bacteria and gold-labeled biological samples.
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| 15. |
- Martin, A. V., et al.
(författare)
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Noise-robust coherent diffractive imaging with a single diffraction pattern
- 2012
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Ingår i: Optics Express. - 1094-4087. ; 20:15, s. 16650-16661
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Tidskriftsartikel (refereegranskat)abstract
- The resolution of single-shot coherent diffractive imaging at X-ray free-electron laser facilities is limited by the low signal-to-noise level of diffraction data at high scattering angles. The iterative reconstruction methods, which phase a continuous diffraction pattern to produce an image, must be able to extract information from these weak signals to obtain the best quality images. Here we show how to modify iterative reconstruction methods to improve tolerance to noise. The method is demonstrated with the hybrid input-output method on both simulated data and single-shot diffraction patterns taken at the Linac Coherent Light Source. (C) 2012 Optical Society of America
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| 16. |
- Nelson, A. J., et al.
(författare)
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Soft x-ray free electron laser microfocus for exploring matter under extreme conditions
- 2009
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Ingår i: Optics Express. - 1094-4087. ; 17:20, s. 18271-18278
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Tidskriftsartikel (refereegranskat)abstract
- We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) -PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of <= 1 mu m. Observations were correlated with simulations of best focus to provide further relevant information.
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| 17. |
- Andreasson, Jakob, et al.
(författare)
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Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser
- 2011
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1539-3755 .- 1550-2376. ; 83:1, s. 016403-
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Tidskriftsartikel (refereegranskat)abstract
- Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 1017 W/cm2 were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 1016 W/cm2. This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.
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| 18. |
- Barty, A., et al.
(författare)
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Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements
- 2012
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Ingår i: Nature Photonics. - 1749-4885 .- 1749-4893. ; 6:1, s. 35-40
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis1. For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been predicted that pulses as short as 10 fs may be required to acquire atomic-resolution structural information1, 2, 3, 4. Here, we describe a mechanism unique to ultrafast, ultra-intense X-ray experiments that allows structural information to be collected from crystalline samples using high radiation doses without the requirement for the pulse to terminate before the onset of sample damage. Instead, the diffracted X-rays are gated by a rapid loss of crystalline periodicity, producing apparent pulse lengths significantly shorter than the duration of the incident pulse. The shortest apparent pulse lengths occur at the highest resolution, and our measurements indicate that current X-ray free-electron laser technology5 should enable structural determination from submicrometre protein crystals with atomic resolution.
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| 19. |
- Loh, N. D., et al.
(författare)
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Cryptotomography : Reconstructing 3D Fourier Intensities from Randomly Oriented Single-Shot Diffraction Patterns
- 2010
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 104:22, s. 225501-1-225501-5
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Tidskriftsartikel (refereegranskat)abstract
- We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compression framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules.
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| 20. |
- Galli, L., et al.
(författare)
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Electronic damage in S atoms in a native protein crystal induced by an intense X-ray free-electron laser pulse
- 2015
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Ingår i: Structural Dynamics. - : AIP Publishing. - 2329-7778. ; 2:4
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Tidskriftsartikel (refereegranskat)abstract
- Current hard X-ray free-electron laser (XFEL) sources can deliver doses to biological macromolecules well exceeding 1 GGy, in timescales of a few tens of femtoseconds. During the pulse, photoionization can reach the point of saturation in which certain atomic species in the sample lose most of their electrons. This electronic radiation damage causes the atomic scattering factors to change, affecting, in particular, the heavy atoms, due to their higher photoabsorption cross sections. Here, it is shown that experimental serial femtosecond crystallography data collected with an extremely bright XFEL source exhibit a reduction of the effective scattering power of the sulfur atoms in a native protein. Quantitative methods are developed to retrieve information on the effective ionization of the damaged atomic species from experimental data, and the implications of utilizing new phasing methods which can take advantage of this localized radiation damage are discussed.
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| 21. |
- Aquila, Andrew, et al.
(författare)
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Time-resolved protein nanocrystallography using an X-ray free-electron laser
- 2012
-
Ingår i: Optics Express. - 1094-4087. ; 20:3, s. 2706-2716
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems.
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| 22. |
- Chapman, Henry, et al.
(författare)
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High-resolution achromatic X-ray optical systems for broad-band imaging and for focusing attosecond pulses
- 2021
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Ingår i: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences. - : Royal Society. - 1364-5021 .- 1471-2946. ; 477:2251
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Tidskriftsartikel (refereegranskat)abstract
- Achromatic focusing systems for hard X-rays are examined which consist of a refractive lens paired with a diffractive lens. Compared with previous analyses, we take into account the behaviour of thick refractive lenses, such as compound refractive lenses and waveguide gradient index refractive lenses, in which both the focal length and the position of the principal planes vary with wavelength. Achromatic systems formed by the combination of such a thick refractive lens with a multilayer Laue lens are found that can operate at a focusing resolution of about 3 nm, over a relative bandwidth of about 1%. With the appropriate distance between the refractive and diffractive lenses, apochromatic systems can also be found, which operate over relative bandwidth greater than 10%. These systems can be used to focus short pulses without distorting them in time by more than several attoseconds. Such systems are suitable for high-flux scanning microscopy and for creating high intensities from attosecond X-ray pulses.
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| 23. |
- Chapman, Henry N, et al.
(författare)
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Femtosecond X-ray protein nanocrystallography.
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 470:7332, s. 73-7
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Tidskriftsartikel (refereegranskat)abstract
- X-ray crystallography provides the vast majority of macromolecular structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been determined despite their importance in all living cells. Here we present a method for structure determination where single-crystal X-ray diffraction 'snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (∼200nm to 2μm in size). We mitigate the problem of radiation damage in crystallography by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage.
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| 24. |
- Johansson, Linda C, 1983, et al.
(författare)
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Lipidic phase membrane protein serial femtosecond crystallography.
- 2012
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Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 9:3, s. 263-265
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet.
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| 25. |
- Koopmann, Rudolf, et al.
(författare)
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In vivo protein crystallization opens new routes in structural biology
- 2012
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Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 9:3, s. 259-262
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Tidskriftsartikel (refereegranskat)abstract
- Protein crystallization in cells has been observed several times in nature. However, owing to their small size these crystals have not yet been used for X-ray crystallographic analysis. We prepared nano-sized in vivo–grown crystals of Trypanosoma brucei enzymes and applied the emerging method of free-electron laser-based serial femtosecond crystallography to record interpretable diffraction data. This combined approach will open new opportunities in structural systems biology.
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