In vitro selection of an allosteric ribozyme that transduces analytes to amplicons

We have selected an allosteric ribozyme ligase from a random sequence popul ation that is activated up to 10,000-fold by oligonucleotide effecters. The ribozyme conforms to a classic two-state model for allostery in which the equilibrium between inactive and active conformers is dramatically altered by the presence of effector ligands. In the presence of the effector the al losteric ribozyme ligase generates templates that can subsequently be ampli fied using conventional amplification technologies, such as RT-PCR. Thus, t he allosteric ribozyme can transduce (or convert) analytes into amplicons. We demonstrate two potential diagnostic applications of the selected allost eric ribozyme ligase:'counting' short oligonucleotide effecters by RT-PCR, and counting a non-nucleic acid effector, ATP, by ligation.