Characterized of radiation-induced thymine-tyrosine crosslinks by electrospray ionization mass spectrometry
- Pacific Northwest Lab., Richland, WA (United States); and others
Exposure to ionizing radiation leads to formation of covalent crosslinks between DNA and proteins. The nature, extent and site of the modifications are now well understood due to the difficulty in assessing free radical-induced damage in biopolymers. Electrospray ionization mass spectrometry (ESI-MS) permits direct analyses of intact oligopeptides, permitting characterization of the radiation-induced DNA-protein covalently crosslinked constituents. Our first application of this methodology to free radical-induced damage was in a model system where angiotensin, a small 10-amino acid peptide, is irradiated at various doses in the presence of excess thymine. The relative yield of crosslinks, which ranged from 0.1 to 15%, was linearly related to radiation dose for doses from 0.1 to 100 Gy. Detection of thymine-tyrosine moieties in this model system was possible at doses at low at 0.1 Gy with a signal-to-noise ratio of 4 to 1. ESIMS revealed that the site of crosslink was located exclusively on the tyrosine residue as expected. 37 refs., 6 figs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 387367
- Journal Information:
- Radiation Research, Journal Name: Radiation Research Journal Issue: 6 Vol. 145; ISSN 0033-7587; ISSN RAREAE
- Country of Publication:
- United States
- Language:
- English
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