The Effects of Ionizing Radiation on Enzymes

Lg, Augenstine

doi:10.1002/9780470124888.ch7

Cited by 17 publications

(2 citation statements)

References 208 publications

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“…Photoinduced oxidative damage can occur directly upon absorption of UV radiation by aromatic residues or indirectly through the generation of reactive oxygen species (ROS) upon absorption of visible light by photosensitizers (Sgarbossa et al, 2003). Less well documented is the sensitivity of disulfide bonds to UV damage (Augenstine, 1962;Augenstine and Ghiron, 1961;Grist et al, 1965). The exact mechanism by which disulfide bonds are destroyed remains unclear; however, recent evidence suggests that aromatic residues close to disulfide bonds are important (Neves-Petersen et al, 2002).…”

Section: Iðhklþmentioning

confidence: 99%

Phasing Macromolecular Structures with UV-Induced Structural Changes

Nanao

Ravelli

2006

Structure

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Experimental phasing of macromolecular crystal structures relies on the accurate measurement of two or more sets of reflections from isomorphous crystals, where the scattering power of a few atoms is different for each set. Recently, it was demonstrated that X-ray-induced intensity differences can also contain phasing information, exploiting specific structural changes characteristic of X-ray damage. This method (radiation damage-induced phasing; RIP) has the advantage that it can be performed on a single crystal of the native macromolecule. However, a drawback is that X-rays introduce many small changes to both solvent and macromolecule. In this study, ultraviolet (UV) radiation has been used to induce specific changes in the macromolecule alone, leading to a larger contrast between radiation-susceptible and nonsusceptible sites. Unlike X-ray RIP, UV RIP does not require the use of a synchrotron. The method has been demonstrated for a series of macromolecules.

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Section: Iðhklþmentioning

confidence: 99%

Phasing Macromolecular Structures with UV-Induced Structural Changes

Nanao

Ravelli

2006

Structure

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“…Despite these previous studies, and after decades of research on the effects of ionizing radiation on biological molecules involved in the immune response at the organismal level (Rao et al , 2005 ; Joo et al , 2015 ), on the killing of cancer cells (for a review see Bernier, 2016 ), on the loss of functionality of organic molecules (Hutchinson and Norcross, 1960 ; Augenstine, 1962 ; Butler and Robins, 1962 ; Orlova, 1993 ), on the radiolysis of small molecules (Kminek and Bada, 2006 ; Portugal et al , 2014 ), and on the damage and fragmentation of biopolymers (Jabir et al , 1989 ), it is still difficult to anticipate the effects of ionizing radiation on all types of biomolecules, because the extent of radiation damage depends on both the radiation dose and the type and size of the molecule. For example, Byun et al ( 2000 ) reported a dramatic drop in the ability of the immunoglobulin E from allergy patients for immunoidentifying the shrimp heat-stable protein in a gamma radiation dose-dependent manner.…”

Section: Introductionmentioning

confidence: 99%

Effects of Gamma and Electron Radiation on the Structural Integrity of Organic Molecules and Macromolecular Biomarkers Measured by Microarray Immunoassays and Their Astrobiological Implications

et al. 2018

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High-energy ionizing radiation in the form of solar energetic particles and galactic cosmic rays is pervasive on the surface of planetary bodies with thin atmospheres or in space facilities for humans, and it may seriously affect the chemistry and the structure of organic and biological material. We used fluorescent microarray immunoassays to assess how different doses of electron and gamma radiations affect the stability of target compounds such as biological polymers and small molecules (haptens) conjugated to large proteins. The radiation effect was monitored by measuring the loss in the immunoidentification of the target due to an impaired ability of the antibodies for binding their corresponding irradiated and damaged epitopes (the part of the target molecule to which antibodies bind). Exposure to electron radiation alone was more damaging at low doses (1 kGy) than exposure to gamma radiation alone, but this effect was reversed at the highest radiation dose (500 kGy). Differences in the dose–effect immunoidentification patterns suggested that the amount (dose) and not the type of radiation was the main factor for the cumulative damage on the majority of the assayed molecules. Molecules irradiated with both types of radiation showed a response similar to that of the individual treatments at increasing radiation doses, although the pattern obtained with electrons only was the most similar. The calculated radiolysis constant did not show a unique pattern; it rather suggested a different behavior perhaps associated with the unique structure of each molecule. Although not strictly comparable with extraterrestrial conditions because the irradiations were performed under air and at room temperature, our results may contribute to understanding the effects of ionizing radiation on complex molecules and the search for biomarkers through bioaffinity-based systems in planetary exploration.

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Zur Abh�ngigkeit der Photosensibilit�t von Aminos�uren von Umgebungsfaktoren

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Biophysik

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The Effects of Ionizing Radiation on Enzymes

Cited by 17 publications

References 208 publications

Phasing Macromolecular Structures with UV-Induced Structural Changes

Phasing Macromolecular Structures with UV-Induced Structural Changes

Effects of Gamma and Electron Radiation on the Structural Integrity of Organic Molecules and Macromolecular Biomarkers Measured by Microarray Immunoassays and Their Astrobiological Implications

Zur Abh�ngigkeit der Photosensibilit�t von Aminos�uren von Umgebungsfaktoren

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