title: Identification of radiation-induced cross-linking between thymine and tryptophan by electrospray ionization-mass spectrometry.
abstract: Upon exposure to ionizing radiation, DNA undergoes a variety of modifications including the production of a covalent bond between the nucleobase thymine and aromatic amino acids. In this work, electrospray ionization-mass spectrometry(ESI-MS) was used to identify the gamma radiation-induced covalent cross-linking of model peptides (sequence YPPW and pYPPW) with the nucleobase thymine. Tandem electrospray ionization-mass spectrometry (ESI-MSn) was employed to investigate the cross-linking sites. The results showed that irrespective of whether tyrosine was phosphorylated or not, the nucleobase thymine was cross-linked with the tryptophan residue. Possible cross-linking mechanisms are proposed by investigating the related mass peaks.
authors.affiliation: Key Laboratory of Bioorganic Phosphorous Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, P.R. China.
authors.forename: Wei-Qun
authors.initials: WQ
authors.lastname: Shi
authors.forename: Jia
authors.initials: J
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Su
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Zhao
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Li
mesh_terms: D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D019000:Phosphotyrosine / Q000737:chemistry / Q000528:radiation effects; D021241:Spectrometry, Mass, Electrospray Ionization; D013941:Thymine / Q000737:chemistry* / Q000528:radiation effects*; D014364:Tryptophan / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D019000:Phosphotyrosine; D014364:Tryptophan; D013941:Thymine