Human cells contain protein specifically binding to a single 1,N6-ethenoadenine in a DNA fragment.
A human DNA binding protein has been characterized from cell-free extracts of liver, placenta, and cultured cells. This protein, apparent molecular mass approximately 35 kDa, to our knowledge, does not resemble other proteins reported to bind to carcinogen-modified DNA. The probe used for characterization was a 25-base oligonucleotide containing a single site-specifically placed 1,N6-ethenoadenine (epsilon A), a product of vinyl chloride metabolism. When annealed to form an epsilon A.T or epsilon A.C pair, a strong affinity to the protein was observed, with a binding constant of approximately 1 x 10(9) M-1. In contrast, very little binding was found with an epsilon A.A pair and none was found with an epsilon A.G pair. This suggests protein recognition of a specific structural alteration. Other defined probes with alkyl adducts did not bind. In addition, the human cell extracts and a rat liver extract were found to nick specifically at the 5' side of the epsilon A adduct, which could indicate a possible associated repair activity.
Rydberg
B
B
Cell and Molecular Biology Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Dosanjh
M K
MK
Singer
B
B
D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism; D001483:Base Sequence; D002850:Chromatography, Gel; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D013379:Substrate Specificity
D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; C007640:1,N(6)-ethenoadenosine; D000241:Adenosine