scholarly journals Enhanced Stability against Radiation Damage of Lysozyme Crystals Grown in Fmoc-CF Hydrogels

2019 ◽  
Vol 19 (8) ◽  
pp. 4229-4233 ◽  
Author(s):  
Rafael Contreras-Montoya ◽  
Albert Castellví ◽  
Guillermo Escolano-Casado ◽  
Judith Juanhuix ◽  
Mayte Conejero-Muriel ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Lysozyme Crystals ◽  
Enhanced Stability ◽  
Stability Against Radiation

scholarly journals Radiation-damage investigation of a DNA 16-mer

2019 ◽  
Vol 26 (4) ◽  
pp. 998-1009 ◽  
Author(s):  
Valéria Bugris ◽  
Veronika Harmat ◽  
Györgyi Ferenc ◽  
Sándor Brockhauser ◽  
Ian Carmichael ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Protein Complex ◽  
Protein Complexes ◽  
Absorbed Dose ◽  
Systematic Investigation ◽  
Egg White Lysozyme ◽  
Dna And Rna ◽  
Radiation Induced ◽  
Density Analysis ◽  
Lysozyme Crystals

In macromolecular crystallography, a great deal of effort has been invested in understanding radiation-damage progression. While the sensitivity of protein crystals has been well characterized, crystals of DNA and of DNA–protein complexes have not thus far been studied as thoroughly. Here, a systematic investigation of radiation damage to a crystal of a DNA 16-mer diffracting to 1.8 Å resolution and held at 100 K, up to an absorbed dose of 45 MGy, is reported. The RIDL (Radiation-Induced Density Loss) automated computational tool was used for electron-density analysis. Both the global and specific damage to the DNA crystal as a function of dose were monitored, following careful calibration of the X-ray flux and beam profile. The DNA crystal was found to be fairly radiation insensitive to both global and specific damage, with half of the initial diffraction intensity being lost at an absorbed average diffraction-weighted dose, D 1/2, of 19 MGy, compared with 9 MGy for chicken egg-white lysozyme crystals under the same beam conditions but at the higher resolution of 1.4 Å. The coefficient of sensitivity of the DNA crystal was 0.014 Å2 MGy−1, which is similar to that observed for proteins. These results imply that the significantly greater radiation hardness of DNA and RNA compared with protein observed in a DNA–protein complex and an RNA–protein complex could be due to scavenging action by the protein, thereby protecting the DNA and RNA in these studies. In terms of specific damage, the regions of DNA that were found to be sensitive were those associated with some of the bound calcium ions sequestered from the crystallization buffer. In contrast, moieties farther from these sites showed only small changes even at higher doses.

Analysis of Radiation Damage in Lysozyme Crystals with High Resolution Triple Axis X-Ray Diffraction

2001 ◽  
Vol 711 ◽  
Author(s):  
Richard J. Matyi ◽  
Heather M. Volz
Keyword(s):  
High Resolution ◽  
Radiation Damage ◽  
Hen Egg White Lysozyme ◽  
X Ray Diffraction ◽  
X Ray ◽  
Egg White Lysozyme ◽  
Peak Intensity ◽  
Angular Extent ◽  
Hen Egg White ◽  
Lysozyme Crystals

ABSTRACTHigh resolution triple axis X-ray diffraction has been used to monitor the effects of X-ray radiation damage in hen egg white lysozyme crystals. At long irradiation the expected decrease in peak intensity and increase in the angular extent of the peak breadth was seen. In contrast, both the intesi-ties and peak breadths exhibited more complex behavior during the initial stages of irradiation. Possible reasons for these observations are discussed.

scholarly journals The early history of cryo-cooling for macromolecular crystallography

IUCrJ ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 148-157 ◽  
Author(s):  
David J. Haas
Keyword(s):  
Lactate Dehydrogenase ◽  
Radiation Damage ◽  
Analytical Data ◽  
Data Bank ◽  
Protein Crystal ◽  
Protein Crystals ◽  
X Ray ◽  
Royal Institution ◽  
History Of ◽  
Lysozyme Crystals

This paper recounts the first successful cryo-cooling of protein crystals that demonstrated the reduction in X-ray damage to macromolecular crystals. The project was suggested by David C. Phillips in 1965 at the Royal Institution of Great Britain and continued in 1967 at the Weizmann Institute of Science, where the first cryo-cooling experiments were performed on lysozyme crystals, and was completed in 1969 at Purdue University on lactate dehydrogenase crystals. A 1970 publication in Acta Crystallographica described the cryo-procedures, the use of cryo-protectants to prevent ice formation, the importance of fast, isotropic cryo-cooling and the collection of analytical data showing more than a tenfold decrease in radiation damage in cryo-cooled lactate dehydrogenase crystals. This was the first demonstration of any method that reduced radiation damage in protein crystals, which provided crystallographers with suitable means to employ synchrotron X-ray sources for protein-crystal analysis. Today, fifty years later, more than 90% of the crystal structures deposited in the Protein Data Bank have been cryo-cooled.

The Mechanical Properties of Cu/TiB2 Multilayer Structures

1990 ◽  
Vol 188 ◽  
Author(s):  
Kevin M. Hubbard ◽  
S. N. Basu ◽  
J-P. Hirvonen ◽  
T. R. Jervis ◽  
M. Nastasi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Radiation Damage ◽  
Tribological Properties ◽  
Martensitic Steel ◽  
Multilayer Structures ◽  
Wear Properties ◽  
Substrate Hardness ◽  
Excellent Stability ◽  
Stability Against Radiation

ABSTRACTWe have investigated the hardness and tribological properties of Cu/TiB2 multilayer structures deposited on substrates of tempered martensitic steel. Films of Cu and TiB2 were also deposited as hardness standards. The wear properties of the films were found to be poor, because of lack of adhesion. However, the films do appear to have good fracture toughness. The hardness of the multilayer was 18% greater than that predicted by the law of mixtures applied to the reference standards and, when corrected for variations in substrate hardness, very nearly equal to that of the TiB2 film. Irradiation by 400 keY Ne-ions to doses of 1.0, 6.0, and 12×1015 ion/cm2 results in a slight hardening of the multilayer. The structure was found to have excellent stability against radiation damage.

Reduction of radiation damage and other benefits of short wavelengths for macromolecular crystallography data collection

2012 ◽  
Vol 45 (4) ◽  
pp. 652-661 ◽  
Author(s):  
Roger Fourme ◽  
Veijo Honkimäki ◽  
Eric Girard ◽  
Kadda Medjoubi ◽  
Anne-Claire Dhaussy ◽  
...  
Keyword(s):  
Data Collection ◽  
Radiation Damage ◽  
Collection Efficiency ◽  
Signal To Noise Ratio ◽  
Global Radiation ◽  
High Energy ◽  
Macromolecular Crystallography ◽  
Data Set ◽  
Good Efficiency ◽  
Lysozyme Crystals

Circumventing radiation damage remains a major problem for X-ray macromolecular crystallography. Analysis of diffraction data collected from normal-sized cryocooled lysozyme crystals shows that the dose required to collect a data set of prescribed resolution and signal-to-noise ratio, assuming an ideally efficient detector, decreases with increasing photon energy in the investigated 6.5–33 keV range. For example, the data collection efficiency is increased by a factor of ∼8 from 8 to 33 keV. Monte Carlo simulations on lysozyme crystals in the range 5–80 keV, taking into account electron escape from samples of different size, also show a positive effect of high energy (albeit less pronounced than in experiments), especially for micrometre-sized samples, and suggest that the optimum energy range is ∼24–41 keV, depending on crystal size. The importance of counting pixel detectors with a good efficiency at high energy is underlined. Macromolecular crystallography beamlines should be modified, or purposely designed, in order to benefit from higher-energy radiation through reduction of global radiation damage, better data accuracy and extension of phasing by anomalous dispersion.

Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

1978 ◽  
Vol 36 (3) ◽  
pp. 61-69
Author(s):  
M. Isaacson ◽  
M.L. Collins ◽  
M. Listvan
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Structural Integrity ◽  
Analytical Electron Microscopy ◽  
High Dose ◽  
Dose Rates ◽  
Special Cases ◽  
Analytical Electron ◽  
Atom Migration ◽  
Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

Radiation Damage in Ceramics

1982 ◽  
Vol 40 ◽  
pp. 600-603
Author(s):  
T. E. Mitchell ◽  
M. R. Pascucci ◽  
R. A. Youngman
Keyword(s):  
Radiation Damage ◽  
Outer Space ◽  
Point Of View ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Storage Media ◽  
Transmission Electron ◽  
Fundamental Point ◽  
Small Defect ◽  
Present Understanding

1. Introduction. Studies of radiation damage in ceramics are of interest not only from a fundamental point of view but also because it is important to understand the behavior of ceramics in various practical radiation enyironments- fission and fusion reactors, nuclear waste storage media, ion-implantation devices, outer space, etc. A great deal of work has been done on the spectroscopy of point defects and small defect clusters in ceramics, but relatively little has been performed on defect agglomeration using transmission electron microscopy (TEM) in the same kind of detail that has been so successful in metals. This article will assess our present understanding of radiation damage in ceramics with illustrations using results obtained from the authors' work.

Review of the Radiation Damage Problem of Organic Specimens in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 476-477
Author(s):  
L. Reimer
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Irradiation Time ◽  
Dose Effect ◽  
Primary Process ◽  
Thin Specimen ◽  
Secondary Damage ◽  
Small Doses ◽  
Micro Organisms ◽  
Damage Processes

Most information about a specimen is obtained by elastic scattering of electrons, but one cannot avoid inelastic scattering and therefore radiation damage by ionisation as a primary process of damage. This damage is a dose effect, being proportional to the product of lectron current density j and the irradiation time t in Coul.cm−2 as long as there is a negligible heating of the specimen.Therefore one has to determine the dose needed to produce secondary damage processes, which can be measured quantitatively by a chemical or physical effect in the thin specimen. The survival of micro-organisms or the decrease of photoconductivity and cathodoluminescence are such effects needing very small doses (see table).

Practical Picture Processing

1974 ◽  
Vol 32 ◽  
pp. 338-339
Author(s):  
T. A. Welton
Keyword(s):  
Radiation Damage ◽  
Coherence Length ◽  
Spatial Information ◽  
State Of The Art ◽  
Coherent Radiation ◽  
The State ◽  
Energy Spread ◽  
Electron Micrograph ◽  
Picture Processing ◽  
Molecular Skeleton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.

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