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Sauer K, Zizak I, Forien JB, Rack A, Scoppola E, Zaslansky P. Primary radiation damage in bone evolves via collagen destruction by photoelectrons and secondary emission self-absorption. Nat Commun 2022; 13:7829. [PMID: 36539409 PMCID: PMC9768145 DOI: 10.1038/s41467-022-34247-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 10/18/2022] [Indexed: 12/24/2022] Open
Abstract
X-rays are invaluable for imaging and sterilization of bones, yet the resulting ionization and primary radiation damage mechanisms are poorly understood. Here we monitor in-situ collagen backbone degradation in dry bones using second-harmonic-generation and X-ray diffraction. Collagen breaks down by cascades of photon-electron excitations, enhanced by the presence of mineral nanoparticles. We observe protein disintegration with increasing exposure, detected as residual strain relaxation in pre-stressed apatite nanocrystals. Damage rapidly grows from the onset of irradiation, suggesting that there is no minimal 'safe' dose that bone collagen can sustain. Ionization of calcium and phosphorous in the nanocrystals yields fluorescence and high energy electrons giving rise to structural damage that spreads beyond regions directly illuminated by the incident radiation. Our findings highlight photoelectrons as major agents of damage to bone collagen with implications to all situations where bones are irradiated by hard X-rays and in particular for small-beam mineralized collagen fiber investigations.
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Affiliation(s)
- Katrein Sauer
- grid.6363.00000 0001 2218 4662Charité – Universitätsmedizin Berlin, Department for Operative, Preventive and Pediatric Dentistry, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
| | - Ivo Zizak
- grid.424048.e0000 0001 1090 3682Helmholtz-Zentrum Berlin, Department for Structure and Dynamics of Energy Materials (SE-ASD), Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Jean-Baptiste Forien
- grid.250008.f0000 0001 2160 9702Lawrence Livermore National Laboratory, Materials Science Division, 7000 East Ave, Livermore, CA 94550 USA
| | - Alexander Rack
- grid.5398.70000 0004 0641 6373ESRF - The European Synchrotron, Structure of Materials Group - ID19, CS 40220, F-38043, Grenoble, Cedex 9 France
| | - Ernesto Scoppola
- grid.461615.10000 0000 8925 2562Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Brandenburg Germany
| | - Paul Zaslansky
- grid.6363.00000 0001 2218 4662Charité – Universitätsmedizin Berlin, Department for Operative, Preventive and Pediatric Dentistry, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
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2
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Fernando NK, Bostrom HLB, Murray CA, Owen RL, Thompson AL, Dickerson JL, Garman EF, Cairns AB, Regoutz A. Variability in X-ray induced effects in [Rh(COD)Cl] 2 with changing experimental parameters. Phys Chem Chem Phys 2022; 24:28444-28456. [PMID: 36399064 PMCID: PMC7614095 DOI: 10.1039/d2cp03928a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
X-ray characterisation methods have undoubtedly enabled cutting-edge advances in all aspects of materials research. Despite the enormous breadth of information that can be extracted from these techniques, the challenge of radiation-induced sample change and damage remains prevalent. This is largely due to the emergence of modern, high-intensity X-ray source technologies and the growing potential to carry out more complex, longer duration in situ or in operando studies. The tunability of synchrotron beamlines enables the routine application of photon energy-dependent experiments. This work explores the structural stability of [Rh(COD)Cl]2, a widely used catalyst and precursor in the chemical industry, across a range of beamline parameters that target X-ray energies of 8 keV, 15 keV, 18 keV and 25 keV, on a powder X-ray diffraction synchrotron beamline at room temperature. Structural changes are discussed with respect to absorbed X-ray dose at each experimental setting associated with the respective photon energy. In addition, the X-ray radiation hardness of the catalyst is discussed, by utilising the diffraction data collected at the different energies to determine a dose limit, which is often considered in protein crystallography and typically overlooked in small molecule crystallography. This work not only gives fundamental insight into how damage manifests in this organometallic catalyst, but will encourage careful consideration of experimental X-ray parameters before conducting diffraction on similar radiation-sensitive organometallic materials.
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Affiliation(s)
- Nathalie K. Fernando
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Hanna L. B. Bostrom
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Claire A. Murray
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Robin L. Owen
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Amber L. Thompson
- Chemical Crystallography, Chemistry Research Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Joshua L. Dickerson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Elspeth F. Garman
- Department of Biochemistry, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Andrew B. Cairns
- Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, SW7 2AZ, UK
| | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
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3
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Xue H, Zhang M, Liu J, Wang J, Ren G. Cryo-electron tomography related radiation-damage parameters for individual-molecule 3D structure determination. Front Chem 2022; 10:889203. [PMID: 36110139 PMCID: PMC9468540 DOI: 10.3389/fchem.2022.889203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/13/2022] [Indexed: 11/28/2022] Open
Abstract
To understand the dynamic structure-function relationship of soft- and biomolecules, the determination of the three-dimensional (3D) structure of each individual molecule (nonaveraged structure) in its native state is sought-after. Cryo-electron tomography (cryo-ET) is a unique tool for imaging an individual object from a series of tilted views. However, due to radiation damage from the incident electron beam, the tolerable electron dose limits image contrast and the signal-to-noise ratio (SNR) of the data, preventing the 3D structure determination of individual molecules, especially at high-resolution. Although recently developed technologies and techniques, such as the direct electron detector, phase plate, and computational algorithms, can partially improve image contrast/SNR at the same electron dose, the high-resolution structure, such as tertiary structure of individual molecules, has not yet been resolved. Here, we review the cryo-electron microscopy (cryo-EM) and cryo-ET experimental parameters to discuss how these parameters affect the extent of radiation damage. This discussion can guide us in optimizing the experimental strategy to increase the imaging dose or improve image SNR without increasing the radiation damage. With a higher dose, a higher image contrast/SNR can be achieved, which is crucial for individual-molecule 3D structure. With 3D structures determined from an ensemble of individual molecules in different conformations, the molecular mechanism through their biochemical reactions, such as self-folding or synthesis, can be elucidated in a straightforward manner.
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Affiliation(s)
- Han Xue
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Meng Zhang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Jianjun Wang
- Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
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4
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Abstract
X-ray crystallography enables detailed structural studies of proteins to understand and modulate their function. Conducting crystallographic experiments at cryogenic temperatures has practical benefits but potentially limits the identification of functionally important alternative protein conformations that can be revealed only at room temperature (RT). This review discusses practical aspects of preparing, acquiring, and analyzing X-ray crystallography data at RT to demystify preconceived impracticalities that freeze progress of routine RT data collection at synchrotron sources. Examples are presented as conceptual and experimental templates to enable the design of RT-inspired studies; they illustrate the diversity and utility of gaining novel insights into protein conformational landscapes. An integrative view of protein conformational dynamics enables opportunities to advance basic and biomedical research.
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5
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Abstract
Microcrystal electron diffraction (MicroED) is a technique for structure determination that relies on the strong interaction of electrons with a minuscule, crystalline sample. While some of the electrons used to probe the crystal interact without altering the crystal, others deposit energy which changes the sample through a series of damage events. It follows that the sample cannot be observed without damaging it, and the frames obtained at the beginning of data collection reflect a crystal that differs from the one that yields the last frames of the dataset. Data acquisition at cryogenic temperatures has been found to reduce the rate of damage progression and is routinely used to increase the dose tolerance of the crystal, allowing more useful data to be obtained before the sample is destroyed. Low-dose data collection can further prolong the lifetime of the crystal, such that less damage is inflicted over the course of data acquisition. Ideally, lower doses increase the measurable volume of a single-crystal lattice by reducing the damage caused by probing electrons. However, the information that can be recovered from a diffraction image is directly related to the number of electrons used to probe the sample. The signal from a weakly exposed crystal runs the risk of being lost in the noise contributed by solvent, crystal disorder, and the electron detection process. This work focuses on obtaining the best possible data from a MicroED measurement, which requires considering several aspects such as sample, dose, and camera type.
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6
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Atakisi H, Conger L, Moreau DW, Thorne RE. Resolution and dose dependence of radiation damage in biomolecular systems. IUCRJ 2019; 6:1040-1053. [PMID: 31709060 PMCID: PMC6830208 DOI: 10.1107/s2052252519008777] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/19/2019] [Indexed: 05/30/2023]
Abstract
The local Fourier-space relation between diffracted intensity I, diffraction wavevector q and dose D, , is key to probing and understanding radiation damage by X-rays and energetic particles in both diffraction and imaging experiments. The models used in protein crystallography for the last 50 years provide good fits to experimental I(q) versus nominal dose data, but have unclear physical significance. More recently, a fit to diffraction and imaging experiments suggested that the maximum tolerable dose varies as q -1 or linearly with resolution. Here, it is shown that crystallographic data have been strongly perturbed by the effects of spatially nonuniform crystal irradiation and diffraction during data collection. Reanalysis shows that these data are consistent with a purely exponential local dose dependence, = I 0(q)exp[-D/D e(q)], where D e(q) ∝ q α with α ≃ 1.7. A physics-based model for radiation damage, in which damage events occurring at random locations within a sample each cause energy deposition and blurring of the electron density within a small volume, predicts this exponential variation with dose for all q values and a decay exponent α ≃ 2 in two and three dimensions, roughly consistent with both diffraction and imaging experiments over more than two orders of magnitude in resolution. The B-factor model used to account for radiation damage in crystallographic scaling programs is consistent with α = 2, but may not accurately capture the dose dependencies of structure factors under typical nonuniform illumination conditions. The strong q dependence of radiation-induced diffraction decays implies that the previously proposed 20-30 MGy dose limit for protein crystallography should be replaced by a resolution-dependent dose limit that, for atomic resolution data sets, will be much smaller. The results suggest that the physics underlying basic experimental trends in radiation damage at T ≃ 100 K is straightforward and universal. Deviations of the local I(q, D) from strictly exponential behavior may provide mechanistic insights, especially into the radiation-damage processes responsible for the greatly increased radiation sensitivity observed at T ≃ 300 K.
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Affiliation(s)
- Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | | | - David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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7
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Hattne J, Martynowycz MW, Penczek PA, Gonen T. MicroED with the Falcon III direct electron detector. IUCRJ 2019; 6:921-926. [PMID: 31576224 PMCID: PMC6760445 DOI: 10.1107/s2052252519010583] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/25/2019] [Indexed: 05/06/2023]
Abstract
Microcrystal electron diffraction (MicroED) combines crystallography and electron cryo-microscopy (cryo-EM) into a method that is applicable to high-resolution structure determination. In MicroED, nanosized crystals, which are often intractable using other techniques, are probed by high-energy electrons in a transmission electron microscope. Diffraction data are recorded by a camera in movie mode: the nanocrystal is continuously rotated in the beam, thus creating a sequence of frames that constitute a movie with respect to the rotation angle. Until now, diffraction-optimized cameras have mostly been used for MicroED. Here, the use of a direct electron detector that was designed for imaging is reported. It is demonstrated that data can be collected more rapidly using the Falcon III for MicroED and with markedly lower exposure than has previously been reported. The Falcon III was operated at 40 frames per second and complete data sets reaching atomic resolution were recorded in minutes. The resulting density maps to 2.1 Å resolution of the serine protease proteinase K showed no visible signs of radiation damage. It is thus demonstrated that dedicated diffraction-optimized detectors are not required for MicroED, as shown by the fact that the very same cameras that are used for imaging applications in electron microscopy, such as single-particle cryo-EM, can also be used effectively for diffraction measurements.
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Affiliation(s)
- Johan Hattne
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Michael W. Martynowycz
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Pawel A. Penczek
- Department of Biochemistry and Molecular Biology, The University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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8
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Dickerson JL, Garman EF. The potential benefits of using higher X-ray energies for macromolecular crystallography. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:922-930. [PMID: 31274414 DOI: 10.1107/s160057751900612x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/01/2019] [Indexed: 05/06/2023]
Abstract
Using X-ray energies higher than those normally used (5-15 keV) for macromolecular X-ray crystallography (MX) at synchrotron sources can theoretically increase the achievable signal as a function of dose and reduce the rate of radiation damage. In practice, a major stumbling block to the use of higher X-ray energy has been the reduced quantum efficiency of silicon detectors as the X-ray energy increases, but hybrid photon-counting CdTe detectors are optimized for higher X-ray energies, and their performance has been steadily improving. Here the potential advantages of using higher incident beam energy together with a CdTe detector for MX are explored, with a particular focus on the advantages that higher beam energies may have for MX experiments with microbeams or microcrystals. Monte Carlo simulations are presented here which for the first time include the efficiency responses of some available X-ray detectors, as well as the possible escape of photoelectrons from the sample and their entry from surrounding material. The results reveal a `sweet spot' at an incident X-ray energy of 26 keV, and show a greater than factor of two improvement in diffraction efficiency at this energy when using microbeams and microcrystals of 5 µm or less.
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Affiliation(s)
- Joshua L Dickerson
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Elspeth F Garman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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9
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Garman EF, Weik M. X-ray radiation damage to biological samples: recent progress. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:907-911. [PMID: 31274412 DOI: 10.1107/s1600577519009408] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 06/30/2019] [Indexed: 05/20/2023]
Abstract
With the continuing development of beamlines for macromolecular crystallography (MX) over the last few years providing ever higher X-ray flux densities, it has become even more important to be aware of the effects of radiation damage on the resulting structures. Nine papers in this issue cover a range of aspects related to the physics and chemistry of the manifestations of this damage, as observed in both MX and small-angle X-ray scattering (SAXS) on crystals, solutions and tissue samples. The reports include measurements of the heating caused by X-ray irradiation in ruby microcrystals, low-dose experiments examining damage rates as a function of incident X-ray energy up to 30 keV on a metallo-enzyme using a CdTe detector of high quantum efficiency as well as a theoretical analysis of the gains predicted in diffraction efficiency using these detectors, a SAXS examination of low-dose radiation exposure effects on the dissociation of a protein complex related to human health, theoretical calculations describing radiation chemistry pathways which aim to explain the specific structural damage widely observed in proteins, investigation of radiation-induced damage effects in a DNA crystal, a case study on a metallo-enzyme where structural movements thought to be mechanism related might actually be radiation-damage-induced changes, and finally a review describing what X-ray radiation-induced cysteine modifications can teach us about protein dynamics and catalysis. These papers, along with some other relevant literature published since the last Journal of Synchrotron Radiation Radiation Damage special issue in 2017, are briefly summarized below.
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Affiliation(s)
- Elspeth F Garman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Martin Weik
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38044 Grenoble, France
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10
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Ueno G, Shimada A, Yamashita E, Hasegawa K, Kumasaka T, Shinzawa-Itoh K, Yoshikawa S, Tsukihara T, Yamamoto M. Low-dose X-ray structure analysis of cytochrome c oxidase utilizing high-energy X-rays. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:912-921. [PMID: 31274413 PMCID: PMC6613116 DOI: 10.1107/s1600577519006805] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/12/2019] [Indexed: 05/29/2023]
Abstract
To investigate the effect of high-energy X-rays on site-specific radiation-damage, low-dose diffraction data were collected from radiation-sensitive crystals of the metal enzyme cytochrome c oxidase. Data were collected at the Structural Biology I beamline (BL41XU) at SPring-8, using 30 keV X-rays and a highly sensitive pixel array detector equipped with a cadmium telluride sensor. The experimental setup of continuous sample translation using multiple crystals allowed the average diffraction weighted dose per data set to be reduced to 58 kGy, and the resulting data revealed a ligand structure featuring an identical bond length to that in the damage-free structure determined using an X-ray free-electron laser. However, precise analysis of the residual density around the ligand structure refined with the synchrotron data showed the possibility of a small level of specific damage, which might have resulted from the accumulated dose of 58 kGy per data set. Further investigation of the photon-energy dependence of specific damage, as assessed by variations in UV-vis absorption spectra, was conducted using an on-line spectrometer at various energies ranging from 10 to 30 keV. No evidence was found for specific radiation damage being energy dependent.
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Affiliation(s)
- Go Ueno
- SR Life Science Instrumentation Team, Life Science Research Infrastructure Group, Advanced Photon Technology Division, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akoh, Hyogo 678-1297, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuya Hasegawa
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Takashi Kumasaka
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akoh, Hyogo 678-1297, Japan
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akoh, Hyogo 678-1297, Japan
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akoh, Hyogo 678-1297, Japan
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masaki Yamamoto
- SR Life Science Instrumentation Team, Life Science Research Infrastructure Group, Advanced Photon Technology Division, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
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11
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Srivastava A, Nagai T, Srivastava A, Miyashita O, Tama F. Role of Computational Methods in Going beyond X-ray Crystallography to Explore Protein Structure and Dynamics. Int J Mol Sci 2018; 19:E3401. [PMID: 30380757 PMCID: PMC6274748 DOI: 10.3390/ijms19113401] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/20/2018] [Accepted: 10/27/2018] [Indexed: 12/13/2022] Open
Abstract
Protein structural biology came a long way since the determination of the first three-dimensional structure of myoglobin about six decades ago. Across this period, X-ray crystallography was the most important experimental method for gaining atomic-resolution insight into protein structures. However, as the role of dynamics gained importance in the function of proteins, the limitations of X-ray crystallography in not being able to capture dynamics came to the forefront. Computational methods proved to be immensely successful in understanding protein dynamics in solution, and they continue to improve in terms of both the scale and the types of systems that can be studied. In this review, we briefly discuss the limitations of X-ray crystallography in studying protein dynamics, and then provide an overview of different computational methods that are instrumental in understanding the dynamics of proteins and biomacromolecular complexes.
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Affiliation(s)
- Ashutosh Srivastava
- Institute of Transformative Bio-Molecules (WPI), Nagoya University, Nagoya, Aichi 464-8601, Japan.
| | - Tetsuro Nagai
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
| | - Arpita Srivastava
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
| | - Osamu Miyashita
- RIKEN-Center for Computational Science, Kobe, Hyogo 650-0047, Japan.
| | - Florence Tama
- Institute of Transformative Bio-Molecules (WPI), Nagoya University, Nagoya, Aichi 464-8601, Japan.
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
- RIKEN-Center for Computational Science, Kobe, Hyogo 650-0047, Japan.
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12
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Kubin M, Kern J, Guo M, Källman E, Mitzner R, Yachandra VK, Lundberg M, Yano J, Wernet P. X-ray-induced sample damage at the Mn L-edge: a case study for soft X-ray spectroscopy of transition metal complexes in solution. Phys Chem Chem Phys 2018; 20:16817-16827. [PMID: 29888772 PMCID: PMC6011208 DOI: 10.1039/c8cp03094d] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
X-ray induced sample damage can impede electronic and structural investigations of radiation-sensitive samples studied with X-rays. Here we quantify dose-dependent sample damage to the prototypical MnIII(acac)3 complex in solution and at room temperature for the soft X-ray range, using X-ray absorption spectroscopy at the Mn L-edge. We observe the appearance of a reduced MnII species as the X-ray dose is increased. We find a half-damage dose of 1.6 MGy and quantify a spectroscopically tolerable dose on the order of 0.3 MGy (1 Gy = 1 J kg-1), where 90% of MnIII(acac)3 are intact. Our dose-limit is around one order of magnitude lower than the Henderson limit (half-damage dose of 20 MGy) which is commonly employed for protein crystallography with hard X-rays. It is comparable, however, to the dose-limits obtained for collecting un-damaged Mn K-edge spectra of the photosystem II protein, using hard X-rays. The dose-dependent reduction of MnIII observed here for solution samples occurs at a dose limit that is two to four orders of magnitude smaller than the dose limits previously reported for soft X-ray spectroscopy of iron samples in the solid phase. We compare our measured to calculated spectra from ab initio restricted active space (RAS) theory and discuss possible mechanisms for the observed dose-dependent damage of MnIII(acac)3 in solution. On the basis of our results, we assess the influence of sample damage in other experimental studies with soft X-rays from storage-ring synchrotron radiation sources and X-ray free-electron lasers.
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Affiliation(s)
- Markus Kubin
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
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13
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Hattne J, Shi D, Glynn C, Zee CT, Gallagher-Jones M, Martynowycz MW, Rodriguez JA, Gonen T. Analysis of Global and Site-Specific Radiation Damage in Cryo-EM. Structure 2018; 26:759-766.e4. [PMID: 29706530 DOI: 10.1016/j.str.2018.03.021] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 02/01/2018] [Accepted: 03/30/2018] [Indexed: 11/20/2022]
Abstract
Micro-crystal electron diffraction (MicroED) combines the efficiency of electron scattering with diffraction to allow structure determination from nano-sized crystalline samples in cryoelectron microscopy (cryo-EM). It has been used to solve structures of a diverse set of biomolecules and materials, in some cases to sub-atomic resolution. However, little is known about the damaging effects of the electron beam on samples during such measurements. We assess global and site-specific damage from electron radiation on nanocrystals of proteinase K and of a prion hepta-peptide and find that the dynamics of electron-induced damage follow well-established trends observed in X-ray crystallography. Metal ions are perturbed, disulfide bonds are broken, and acidic side chains are decarboxylated while the diffracted intensities decay exponentially with increasing exposure. A better understanding of radiation damage in MicroED improves our assessment and processing of all types of cryo-EM data.
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Affiliation(s)
- Johan Hattne
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles CA 90095, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Dan Shi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Calina Glynn
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chih-Te Zee
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Marcus Gallagher-Jones
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael W Martynowycz
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles CA 90095, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Jose A Rodriguez
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles CA 90095, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Departments of Physiology and Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA 90095, USA.
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14
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Abstract
Radiation damage still remains a major limitation and challenge in macromolecular X-ray crystallography. Some of the high-intensity radiation used for diffraction data collection experiments is absorbed by the crystals, generating free radicals. These give rise to radiation damage even at cryotemperatures (~100 K), which can lead to incorrect biological conclusions being drawn from the resulting structure, or even prevent structure solution entirely. Investigation of mitigation strategies and the effects caused by radiation damage has been extensive over the past fifteen years. Here, recent understanding of the physical and chemical phenomena of radiation damage is described, along with the global effects inflicted on the collected data and the specific effects observed in the solved structure. Furthermore, this review aims to summarise the progress made in radiation damage studies in macromolecular crystallography from the experimentalist’s point of view and to give an introduction to the current literature.
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15
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Warkentin MA, Atakisi H, Hopkins JB, Walko D, Thorne RE. Lifetimes and spatio-temporal response of protein crystals in intense X-ray microbeams. IUCRJ 2017; 4:785-794. [PMID: 29123681 PMCID: PMC5668864 DOI: 10.1107/s2052252517013495] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/20/2017] [Indexed: 05/22/2023]
Abstract
Serial synchrotron-based crystallography using intense microfocused X-ray beams, fast-framing detectors and protein microcrystals held at 300 K promises to expand the range of accessible structural targets and to increase overall structure-pipeline throughputs. To explore the nature and consequences of X-ray radiation damage under microbeam illumination, the time-, dose- and temperature-dependent evolution of crystal diffraction have been measured with maximum dose rates of 50 MGy s-1. At all temperatures and dose rates, the integrated diffraction intensity for a fixed crystal orientation shows non-exponential decays with dose. Non-exponential decays are a consequence of non-uniform illumination and the resulting spatial evolution of diffracted intensity within the illuminated crystal volume. To quantify radiation-damage lifetimes and the damage state of diffracting crystal regions, a revised diffraction-weighted dose (DWD) is defined and it is shown that for Gaussian beams the DWD becomes nearly independent of actual dose at large doses. An apparent delayed onset of radiation damage seen in some intensity-dose curves is in fact a consequence of damage. Intensity fluctuations at high dose rates may arise from the impulsive release of gaseous damage products. Accounting for these effects, data collection at the highest dose rates increases crystal radiation lifetimes near 300 K (but not at 100 K) by a factor of ∼1.5-2 compared with those observed at conventional dose rates. Improved quantification and modeling of the complex spatio-temporal evolution of protein microcrystal diffraction in intense microbeams will enable more efficient data collection, and will be essential in improving the accuracy of structure factors and structural models.
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Affiliation(s)
- Matthew A. Warkentin
- Physics Department, Cornell University, Clark Hall, Ithaca, NY 14853, USA
- Rubota Corporation, 1260 NW Naito Parkway #609, Portland, OR 97209, USA
| | - Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | | | - Donald Walko
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
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16
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Hegde RP, Fedorov AA, Sauder JM, Burley SK, Almo SC, Ramagopal UA. The hidden treasure in your data: phasing with unexpected weak anomalous scatterers from routine data sets. Acta Crystallogr F Struct Biol Commun 2017; 73:184-195. [PMID: 28368276 PMCID: PMC5379167 DOI: 10.1107/s2053230x17002680] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/16/2017] [Indexed: 12/25/2022] Open
Abstract
Single-wavelength anomalous dispersion (SAD) utilizing anomalous signal from native S atoms, or other atoms with Z ≤ 20, generally requires highly redundant data collected using relatively long-wavelength X-rays. Here, the results from two proteins are presented where the anomalous signal from serendipitously acquired surface-bound Ca atoms with an anomalous data multiplicity of around 10 was utilized to drive de novo structure determination. In both cases, the Ca atoms were acquired from the crystallization solution, and the data-collection strategy was not optimized to exploit the anomalous signal from these scatterers. The X-ray data were collected at 0.98 Å wavelength in one case and at 1.74 Å in the other (the wavelength was optimized for sulfur, but the anomalous signal from calcium was exploited for structure solution). Similarly, using a test case, it is shown that data collected at ∼1.0 Å wavelength, where the f'' value for sulfur is 0.28 e, are sufficient for structure determination using intrinsic S atoms from a strongly diffracting crystal. Interestingly, it was also observed that SHELXD was capable of generating a substructure solution from high-exposure data with a completeness of 70% for low-resolution reflections extending to 3.5 Å resolution with relatively low anomalous multiplicity. Considering the fact that many crystallization conditions contain anomalous scatterers such as Cl, Ca, Mn etc., checking for the presence of fortuitous anomalous signal in data from well diffracting crystals could prove useful in either determining the structure de novo or in accurately assigning surface-bound atoms.
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Affiliation(s)
- Raghurama P. Hegde
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, #4, 16th Cross, Sadashivnagar, Bangalore 560 080, India
| | - Alexander A. Fedorov
- Department of Biochemistry, Albert Einstein College of Medicine, Ullmann Building, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - J. Michael Sauder
- Lilly Biotechnology Center, Eli Lilly and Company, 10290 Campus Point Drive, San Diego, CA 92121, USA
| | - Stephen K. Burley
- RCSB Protein Data Bank, Center for Integrative Proteomics Research, Rutgers University, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Institute of Quantitative Biomedicine, Rutgers University, The State University of New Jersey, Piscataway, NJ 08854, USA
- Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08903, USA
- RCSB Protein Data Bank, San Diego Supercomputer Center, San Diego, California, USA
- Skaggs School of Pharmacy and Pharmceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Steven C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Ullmann Building, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Udupi A. Ramagopal
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, #4, 16th Cross, Sadashivnagar, Bangalore 560 080, India
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17
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Abstract
Radiation damage inflicted on macromolecular crystals during X-ray diffraction experiments remains a limiting factor for structure solution, even when samples are cooled to cryotemperatures (~100 K). Efforts to establish mitigation strategies are ongoing and various approaches, summarized below, have been investigated over the last 15 years, resulting in a deeper understanding of the physical and chemical factors affecting damage rates. The recent advent of X-ray free electron lasers permits "diffraction-before-destruction" by providing highly brilliant and short (a few tens of fs) X-ray pulses. New fourth generation synchrotron sources now coming on line with higher X-ray flux densities than those available from third generation synchrotrons will bring the issue of radiation damage once more to the fore for structural biologists.
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Affiliation(s)
- Elspeth F Garman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Martin Weik
- Institut de Biologie Structurale, University of Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38044, Grenoble, France.
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18
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Hasegawa K, Yamashita K, Murai T, Nuemket N, Hirata K, Ueno G, Ago H, Nakatsu T, Kumasaka T, Yamamoto M. Development of a dose-limiting data collection strategy for serial synchrotron rotation crystallography. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:29-41. [PMID: 28009544 PMCID: PMC5182019 DOI: 10.1107/s1600577516016362] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/13/2016] [Indexed: 05/22/2023]
Abstract
Serial crystallography, in which single-shot diffraction images are collected, has great potential for protein microcrystallography. Although serial femtosecond crystallography (SFX) has been successfully demonstrated, limited beam time prevents its routine use. Inspired by SFX, serial synchrotron crystallography (SSX) has been investigated at synchrotron macromolecular crystallography beamlines. Unlike SFX, the longer exposure time of milliseconds to seconds commonly used in SSX causes radiation damage. However, in SSX, crystals can be rotated during the exposure, which can achieve efficient coverage of the reciprocal space. In this study, mercury single-wavelength anomalous diffraction (Hg-SAD) phasing of the luciferin regenerating enzyme (LRE) was performed using serial synchrotron rotation crystallography. The advantages of rotation and influence of dose on the data collected were evaluated. The results showed that sample rotation was effective for accurate data collection, and the optimum helical rotation step depended on multiple factors such as multiplicity and partiality of reflections, exposure time per rotation angle and the contribution from background scattering. For the LRE microcrystals, 0.25° was the best rotation step for the achievable resolution limit, whereas a rotation step larger than or equal to 1° was favorable for Hg-SAD phasing. Although an accumulated dose beyond 1.1 MGy caused specific damage at the Hg site, increases in resolution and anomalous signal were observed up to 3.4 MGy because of a higher signal-to-noise ratio.
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Affiliation(s)
- Kazuya Hasegawa
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo 679-5198, Japan
| | | | - Tomohiro Murai
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Nipawan Nuemket
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo 679-5198, Japan
| | - Kunio Hirata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo 679-5148, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Go Ueno
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo 679-5148, Japan
| | - Hideo Ago
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo 679-5148, Japan
| | - Toru Nakatsu
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo 679-5148, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Takashi Kumasaka
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo 679-5148, Japan
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19
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Bury CS, McGeehan JE, Antson AA, Carmichael I, Gerstel M, Shevtsov MB, Garman EF. RNA protects a nucleoprotein complex against radiation damage. Acta Crystallogr D Struct Biol 2016; 72:648-57. [PMID: 27139628 PMCID: PMC4854314 DOI: 10.1107/s2059798316003351] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/26/2016] [Indexed: 11/10/2022] Open
Abstract
Radiation damage during macromolecular X-ray crystallographic data collection is still the main impediment for many macromolecular structure determinations. Even when an eventual model results from the crystallographic pipeline, the manifestations of radiation-induced structural and conformation changes, the so-called specific damage, within crystalline macromolecules can lead to false interpretations of biological mechanisms. Although this has been well characterized within protein crystals, far less is known about specific damage effects within the larger class of nucleoprotein complexes. Here, a methodology has been developed whereby per-atom density changes could be quantified with increasing dose over a wide (1.3-25.0 MGy) range and at higher resolution (1.98 Å) than the previous systematic specific damage study on a protein-DNA complex. Specific damage manifestations were determined within the large trp RNA-binding attenuation protein (TRAP) bound to a single-stranded RNA that forms a belt around the protein. Over a large dose range, the RNA was found to be far less susceptible to radiation-induced chemical changes than the protein. The availability of two TRAP molecules in the asymmetric unit, of which only one contained bound RNA, allowed a controlled investigation into the exact role of RNA binding in protein specific damage susceptibility. The 11-fold symmetry within each TRAP ring permitted statistically significant analysis of the Glu and Asp damage patterns, with RNA binding unexpectedly being observed to protect these otherwise highly sensitive residues within the 11 RNA-binding pockets distributed around the outside of the protein molecule. Additionally, the method enabled a quantification of the reduction in radiation-induced Lys and Phe disordering upon RNA binding directly from the electron density.
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Affiliation(s)
- Charles S. Bury
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, England
| | - John E. McGeehan
- Molecular Biophysics, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, King Henry I Street, Portsmouth PO1 2DY, England
| | - Alfred A. Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York Y010 5DD, England
| | - Ian Carmichael
- Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Markus Gerstel
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, England
| | - Mikhail B. Shevtsov
- Laboratory of Structural Biology of GPCRs, Moscow Institute of Physics and Technology, Dolgoprudniy 141700, Russian Federation
| | - Elspeth F. Garman
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, England
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20
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Dauter Z. Objective evaluation of radiation damage in a nucleoprotein complex. Acta Crystallogr D Struct Biol 2016; 72:601-2. [PMID: 27139623 PMCID: PMC4931811 DOI: 10.1107/s2059798316006550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Systematic analysis of a protein–RNA complex has shown how nucleoprotein complexes can be protected from radiation damage.
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Affiliation(s)
- Zbigniew Dauter
- Macromolecular Crystallography Laboratory, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439, USA
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21
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Huang CY, Olieric V, Ma P, Howe N, Vogeley L, Liu X, Warshamanage R, Weinert T, Panepucci E, Kobilka B, Diederichs K, Wang M, Caffrey M. In meso in situ serial X-ray crystallography of soluble and membrane proteins at cryogenic temperatures. Acta Crystallogr D Struct Biol 2016; 72:93-112. [PMID: 26894538 PMCID: PMC4756617 DOI: 10.1107/s2059798315021683] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/15/2015] [Indexed: 11/21/2022] Open
Abstract
Here, a method for presenting crystals of soluble and membrane proteins growing in the lipid cubic or sponge phase for in situ diffraction data collection at cryogenic temperatures is introduced. The method dispenses with the need for the technically demanding and inefficient crystal-harvesting step that is an integral part of the lipid cubic phase or in meso method of growing crystals. Crystals are dispersed in a bolus of mesophase sandwiched between thin plastic windows. The bolus contains tens to hundreds of crystals, visible with an in-line microscope at macromolecular crystallography synchrotron beamlines and suitably disposed for conventional or serial crystallographic data collection. Wells containing the crystal-laden boluses are removed individually from hermetically sealed glass plates in which crystallization occurs, affixed to pins on goniometer bases and excess precipitant is removed from around the mesophase. The wells are snap-cooled in liquid nitrogen, stored and shipped in Dewars, and manually or robotically mounted on a goniometer in a cryostream for diffraction data collection at 100 K, as is performed routinely with standard, loop-harvested crystals. The method is a variant on the recently introduced in meso in situ serial crystallography (IMISX) method that enables crystallographic measurements at cryogenic temperatures where crystal lifetimes are enormously enhanced whilst reducing protein consumption dramatically. The new approach has been used to generate high-resolution crystal structures of a G-protein-coupled receptor, α-helical and β-barrel transporters and an enzyme as model integral membrane proteins. Insulin and lysozyme were used as test soluble proteins. The quality of the data that can be generated by this method was attested to by performing sulfur and bromine SAD phasing with two of the test proteins.
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Affiliation(s)
- Chia-Ying Huang
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, D02 R590, Ireland
| | - Vincent Olieric
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Pikyee Ma
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, D02 R590, Ireland
- Laboratory of Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Nicole Howe
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, D02 R590, Ireland
| | - Lutz Vogeley
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, D02 R590, Ireland
| | - Xiangyu Liu
- School of Medicine, Tsinghua University, Beijing 100084, People’s Republic of China
| | | | - Tobias Weinert
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Ezequiel Panepucci
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Brian Kobilka
- School of Medicine, Tsinghua University, Beijing 100084, People’s Republic of China
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kay Diederichs
- Fachbereich Biologie, Universität Konstanz, Box 647, D-78457 Konstanz, Germany
| | - Meitian Wang
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Martin Caffrey
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College, Dublin 2, D02 R590, Ireland
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