Nucleic acid conformation diversity: from structure to function and regulation

Nucleic acids are the structural supports of genetic material and therefore the key factors in many vital cellular processes. The double-stranded righ t-handed helix is a regular conformation adopted by both DNA and RNA in cel ls, but an increasing number of results point to the biological importance of alternative structures such as bulges, hairpins, branched junctions or q uadruplexes. Progress in the chemical synthesis of oligonucleotides and in the knowledge of the factors that favour a particular conformation has open ed new fields of research in molecular recognition and drug design.