DNA-protein crosslinks induced by bis-functional electrophiles

TOXI 36

Elisabeth M. Loecken, elisabeth.m.loecken@vanderbilt.edu, Department of Biochemistry, Vanderbilt University, Nashville, TN 37235, Amy Joan L. Ham, amy.ham@Vanderbilt.Edu, Department of Biochemistry, Mass Spectrometry Research Center, Vanderbilt University, 9114C Medical Research Building III, 465 21st Avenue South, Nashville, TN 37232-8575, D. C. Liebler, Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, and F. Peter Guengerich, Dept. of Biochemistry & Center in Molecular Toxicology, Vanderbilt University, 638 Robinson Research Bldg, 23rd & Pierce Avenues, Nashville, TN 37232.
Mass spectral approaches have been used to screen human fibroblast nuclei for proteins with nucleophilic sites that may undergo reactions with bis-functional electrophiles to form DNA-protein crosslinks. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was identified as a potential candidate for crosslinking to DNA through an active site cysteine residue (Cys246). Electrophoretic mobility shift assays confirm the formation of crosslinks between GAPDH and oligonucleotides in the presence of ethylene dibromide, butadiene diepoxide, and dibromomethane. Active site cysteine (Cys 246) adducts were observed in the mass spectral analysis of ethylene dibromide and butadiene diepoxide-treated GAPDH. Proteomic screening is currently underway with human liver nuclei and bacterial cells to identify other proteins that crosslink to DNA in the presence of bis-functional electrophiles. (Supported in part by USPHS R01 ES10546, T32 ES07028)
 

General Papers: Young Investigator Session
8:00 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 308, Oral

Division of Chemical Toxicology

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006