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Long‐range interactions between DNA‐bound ligands
Author(s) -
Samuelson Per,
Jensen Karl,
Kubista Mikael
Publication year - 1994
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.300070313
Subject(s) - dapi , cooperativity , allosteric regulation , cooperative binding , dna , chemistry , biophysics , circular dichroism , fluorescence , conformational change , binding site , stereochemistry , biochemistry , biology , receptor , apoptosis , physics , quantum mechanics
We have studied the interaction of the A:T specific minor‐groove binding ligand 4′, 6‐diamidino‐2‐phenylindole (DAPI) with synthetic DNA oligomers containing specific binding sites in order to investigate possible long‐range interactions between bound ligands. We find that DAPI binds cooperatively to the oligomers. The degree of cooperativity increases with increasing number of binding sites and decreases with the separation between them. This dependence is paralleled by changes in the induced circular dichroism spectrum of DAPI, which decreases in intensity at 335 nm and increases at 365 nm. These results are consistent with an allosteric interaction of DAPI with DNA, where bound ligands cooperatively alter the structure of the DNA molecule. This structural change seems possible to induce under various conditions, including physiological. One consequence of allosteric binding is that ligands bound at a distance from each other sense each other's presence and influence each other's properties. If some regulatory proteins the same conformational change as DAPI, novel mechanisms for controlling gene expression can be anticipated.