An in vitro study of the interaction of some sulphur-containing diamines with DNA

This work has been carried out investigating some sulfur-containing diamines, such as lanthionamine, cystathionamine, cystamine and homocystamine, synthesized in our laboratory, in their interaction with DNA, using natural polyamines as references compounds. The analyses of experimental data obtained either by ethidium bromide displacement assays, or by thermal denaturation, show that sulfur containing diamines have DNA binding properties more similar to shorter chain polyamines putrescine and cadaverine than spermidine and spermine: but they do not explain anything on the nature of these interactions. On the contrary the study on DNA B/A transition emphasizes an interesting and unexpected behaviour of cystamine, and homocystamine, the only diamines containing a disulfide bridge. We think that this effect could result by affecting the hydration properties of DNA in an indirect way.