Restriction enzyme inhibition and lambda exonuclease studies indicate that carcinogen N-acetoxy-N-acetyl-2 aminofluorene (AAAF) binds to sequences on ɸX174 RF and SV40 plasmids DNA that are similar to the eight preferred binding sites previously located on pBR 322.
Both DNAs were digested with enzyme Hinf I and resultant fragments 32P end-labeled. Labeled fragments were reacted with the carcinogen to give one to sixteen bound moieties per DNA. Fragments were isolated and restriccion enzyme and lambda exonuclease inhibition assays were performed.
Inhibition detected occurred at selected sites and was not specific for a certain enzyme or certain size of recognition sequence.
Results of these assays allow mapping of the location of high affinity binding sites of the carcinogen on both DNAs.
All sites have common sequence elements: the presence of either the sequence T(G/C)TT(G/C) or the sequence T(G/C) CTT(G/C).