A new DNA minor groove binding motif: Cross-linked lexitropsins

Article abstract of DOI:10.1021/ja00095a001

The nitrogen atoms of central pyrrole rings on two separate tripyrrolecarboxamide strands were covalently linked through poly(methylene) chains to provide a novel class of lexitropsins potentially capable of B-DNA double-strand reading via the minor groove. CD titration experiments revealed increasingly enhanced binding of 1:1 stoichiometry to the poly(dA-dT)- poly(dA-dT) DNA from the tetrakis(methylene) linkage to the heptakis(methylene) linkage, suggesting gradually growing importance of the bidentate antiparallel side by side binding. Ethidium bromide fluorescence displacement experiments on both poly(dA-dT)-poly(dA-dT) and poly(dA)- poly(dT) DNA's supported this analysis by providing quantitative measurement of intrinsic binding constants. The heptakis(methylene) linkage offered a binding enhancement of approximately 1000 times compared with that of the monomer.