High mobility group 1 and 2 proteins bind preferentially to DNA that contains bulky adducts induced by benzo[a]pyrene diol epoxide and N-acetoxy-acetylaminofluorene

High mobility group (HMG) proteins 1 and 2 are abundant non-histone chromos omal proteins that bind preferentially DNA that is bent or underwound. Prev ious studies have shown that these proteins preferentially bind to DNA dama ged by the crosslinking agents cis-diammine-dichloro-platinum(II), chromium (III) and UV-C radiation. Here we have studied the binding of HMG-1/2 prote ins to a duplex oligonucleotide damaged by benzo(a)pyrene diol epoxide or N -acetoxy-acetylaminofluorene using an electrophoretic mobility shift assay. Both chemicals induce monoadducts that are known to distort DNA structure, The affinities of HMC-1/2 for DNA damaged by benzo[a]pyrene diol epoxide o r N-acetoxy-acetylaminofluorene were similar to that for UV-irradiated DNA, which were an order of magnitude higher than for undamaged DNA. In contras t, DNA modified by dimethyl sulfate was not preferentially recognised by HM G-1/2. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.