DNA aptamers and DNA enzymes.

Investigators using combinatorial methods are revealing the surprising structural and functional abilities of DNA. A consequence of DNA's structure-forming potential is its ability to form highly specific receptors and ligands, and even its ability to catalyze chemical reactions. Unlike the classical images of double-stranded DNA, these DNA structures have many of the higher-ordered structural features that are found with ribozymes and other folded RNAs. Recent research is beginning to indicate that these new DNA structures are not rare exceptions, and that DNA, despite the absence of 2' hydroxyl groups, could rival RNA in its ability to form intricate structures and in its ability to function as an enzyme.