Helicenes in Biochemistry

Abstract

In this chapter, the applications of helicenes in biochemistry including their interactions with biomolecules and cell imaging are summarized. It was found that the helicene amine shows the chiral recognition toward DNA/nucleosides. Studies on the selective binding of helicenes to Z-DNA and B-DNA suggested that the amino groups on helicene skeletons are essential for the interaction with Z-DNA. The interactions between N-methyl-5-aza[5]helicenium salts and DNA show marked counterion effects. Effective inhibition of telomerase by small molecules bridged helicenes indicates that appropriate interplanar angle and helicity are of great importance. Moreover, the investigation on the interactions between spermine-functionalized optically pure [5]helicene and B-, and Z-DNA indicates that (P)-isomer shows a strong affinity to B-DNA, while (M)-isomer displays preference to Z-DNA. Because of the π-conjugated helical structures, helicenes can also be applied to cell imaging. Thus, a series of tetrahydrohelicene nanoparticles for fluorescence cell imaging show interesting structure-dependent distribution, which provides a new perspective for the design of fluorescence probes. In addition, thiahelicene labeled by rhodamine probe can also visualize the loaded nanoparticles in cell.