Topologically Modified Biopolymers: Properties of Synthetic Circular DNAs and RNAs

Circular nucleic acid molecules can have chemical and biological properties very different from those of the corresponding linear nucleic acid polymers. Described here are methods used recently for construction of such circular molecules, and some of the properties that can arise from making this topological change. Among the unusual properties found for circular nucleic acids are: strong resistance to degradation in biological media; high affinity of binding to other nucleic acids; high sequence selectivity in nucleic acid binding; topological linkage to biomolecules; and the ability to template the synthesis of specific repeating nucleic acid and protein polymers. These properties may be useful in biochemical, medical diagnostic and therapeutic applications.