Model of Tracks of Ionizing Radiations for Radical Reaction Mechanisms

Mozumder, A.; Magee, John L.

doi:10.2307/3572190

Cited by 225 publications

(64 citation statements)

References 10 publications

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“…The existence of a "track core" in the radial distribution of dose has been postulated by some authors (Mozumder and Magee, 1966;Magee and Chatterjee, 1980;Chatterjee and Magee, 1980), as connected with the Bohr adiabatic radius (e.g. Brandt and Ritchie, 1974).…”

Section: Discussionmentioning

confidence: 92%

The radial distribution of dose around the path of a heavy ion in liquid water

Waligórski

Hamm

Katz

1986

International Journal of Radiation Applications and Instrumenta

472

243

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Section: Discussionmentioning

confidence: 92%

The radial distribution of dose around the path of a heavy ion in liquid water

Waligórski

Hamm

Katz

1986

International Journal of Radiation Applications and Instrumenta

472

243

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“…Ionizing radiation deposits energy nonhomogeneously in a cell generating free radicals that individually stimulate base loss and strand breakage (21). Two random single-strand breakages on opposite DNA strands that are spaced nearby will produce DSBs with variable overhanging ends.…”

Section: Discussionmentioning

confidence: 99%

A link between double-strand break-related repair and V(D)J recombination: the scid mutation.

Hendrickson

Qin

Bump

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

255

141

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We show here that mammalian site-specific recombination and DNA-repair pathways share a common factor. The effects of DNA-damaging agents on cell lines derived from mice homozygous for the scid (severe combined immune deficiency) mutation were studied. Surprisingly, all scid cell lines exhibited a profound hypersensitivity to DNAdamaging agents that caused double-strand breaks (xirradiation and bleomycin) but not to other chemicals that caused single-strand breaks or cross-links. Neutral filter elution assays demonstrated that the x-irradiation hypersensitivity could be correlated with a deficiency in repairing double-strand breaks. These data suggest that the scid gene product is involved in two pathways: DNA repair of random doublestrand breaks and the site-specific and lymphoid-restricted variable-(diversity)-joining [V(D)J] DNA rearrangement process. We propose that the scid gene product performs a similar function in both pathways and may be a ubiquitous protein.Mice homozygous for the scid (severe combined immune deficiency) mutation lack a functional immune system but otherwise appear normal (1). The absence of B and T lymphocytes in scid mice is due to a defect in the site-specific V(D)J recombination pathway that is responsible for the somatic assembly of immunoglobulin and T-cell receptor genes. Analysis of scid variable (diversity) joining [V(D)J] recombination events has shown that large deletions, which remove all or most of the coding sequences of immunoglobulin or T-cell receptor genes, accompany the rearrangements and result in nonfunctional lymphoid cells (2-4). Furthermore, examination of model rearrangement templates (recombinant retroviruses and plasmids) introduced into scid lymphoid cells has recapitulated the aberrant deletional rearrangements (4-6). Thus, we and others have proposed that the scid gene product is an integral component of the V(D)J recombinase complex.Mutations that affect site-specific and general recombination frequently also affect the pathways responsible for repairing DNA double-strand breaks (DSBs) due to chromosome damage (7). This overlap of recombination and DSBrepair pathways is presumed to result from the postulated role of double-stranded ends as structural intermediates in many types of recombination and repair (for review, see ref.8). DSBs can also be generated by a number of DNAdamaging agents, the most common of which is ionizing radiation. X-ray-induced DSBs can stimulate chromosomal deletions and aberrant rearrangements and are lethal if not repaired (9). We show here that the similarity between recombination and DSB-repair pathways extends to mammalian cells affected by the scid mutation. scid cells were found to be hypersensitive specifically to agents that make DSBs. In addition, a dynamic assay for DNA repair demonstrated that the scid mutation severely diminished DSB repair. We propose that the scid gene product performs a similar function in both the V(D)J recombination and DSBrepair pathways. MATERIALS AND METHODSFibroblastic Cell Lines. Fib...

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“…Ninety percent of the photons at this energy interact with the sample through the photoelectric effect. A single absorbed photon leads to the generation of Ϸ300 electrons at this energy (23,24).…”

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confidence: 99%

Structure and quantum chemical characterization of chloroperoxidase compound 0, a common reaction intermediate of diverse heme enzymes

Kühnel

Derat

Terner

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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We have determined the crystal structure of the chloroperoxidase (CPO) hydroperoxo reaction intermediate (CPO compound 0) at 1.75-Å resolution. The intermediate was generated through controlled photoreduction of the CPO oxygen complex during x-ray data collection, which was monitored by recording of the crystal absorption spectra. Initially, the peroxo-anion species was formed and then protonated to yield compound 0. Quantum chemical calculations indicate that the peroxo-anion species is not stable and collapses instantaneously to compound 0. Compound 0 is present in the ferric low-spin doublet ground state and is characterized by a long OOO bond length of 1.5 Å and a FeOO bond distance of 1.8 Å, which is also observed in the crystal structure.crystal structure ͉ protein structure/function ͉ radiolysis ͉ reaction mechanism ͉ QM/MM calculations

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Model of Tracks of Ionizing Radiations for Radical Reaction Mechanisms

Cited by 225 publications

References 10 publications

The radial distribution of dose around the path of a heavy ion in liquid water

The radial distribution of dose around the path of a heavy ion in liquid water

A link between double-strand break-related repair and V(D)J recombination: the scid mutation.

Structure and quantum chemical characterization of chloroperoxidase compound 0, a common reaction intermediate of diverse heme enzymes

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