FIGURE 3.
Allosteric (A) and inhibitor (B) control strategies for protein-mediated modulation of ribozyme activity, illustrated with the hammerhead ribozyme. In the classification proposed here, the inhibitor control strategies are not truly “allosteric” in that they do not involve a communication module. Instead, the inhibitor oligonucleotide strand binds in direct competition with the ribozyme’s substrate. In principle, small molecules could also function as the inhibitor (see text). (C) The TRAP strategy of Burke et al. (2002). (D) The expansive regulation strategy of Sen and coworkers (Wang and Sen 2001; Wang et al. 2002a).
