Open AccessDNA‐sequence binding preference of the GC‐selective ligand mithramycin
Author(s) -
CARPENTER Mark L.,
MARKS Jonathan N.,
FOX Keith R.
Publication year - 1993
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1993.tb18066.x
Subject(s) - deoxyribonuclease , deoxyribonuclease i , dna footprinting , footprinting , dna , cleavage (geology) , base pair , chemistry , stereochemistry , biochemistry , ligand (biochemistry) , microbiology and biotechnology , biology , dna binding protein , base sequence , transcription factor , gene , receptor , paleontology , fracture (geology)
We have used hydroxy‐radical and deoxyribonuclease‐I footprinting to probe the interaction of mithramycin with DNA fragments containing the sequences (AT) 10 X(AT) 10 (X = CCCG, CCGC or CGGC) and A 14 GCCCT 15 . As expected the drug produces clear footprints located around the central four GC base pairs. The exact position of the footprint is different for the four sequences; the footprint with CCCG is displaced by two base pairs in the 5′ direction relative to GCCC. These variations are explained by suggesting that mithramycin avoids the dinucleotide CG and binds better to GG/CC than GC. Although there is little change in deoxyribonuclease‐I cleavage of the surrounding blocks of (AT) n . cleavage by deoxyribonuclease II is markedly enhanced and certain thymines on the 5′ side of the ligand‐binding site become hyperreactive to hydroxy‐radical attack. Adjacent regions of A n · T n show enhanced rates of deoxyribonuclease‐I cleavage in the presence of the antibiotic.