ORGN 614 |
| Donald H. Burke, Vanvimon Sakmerprome, and Sanchita Hati. Department of Chemistry, Indiana University, Bloomington, IN 47405 |
| RNA assembly can be regulated through interactions with metal ions or allosteric effectors. The SH1 RNA isolated in our lab is the first to utilize Ni(II) to assemble a non-covalent complex with a substrate. It appears to bridge a specific internal guanosine with exogenous biocytin (e-biotinylated Lys). The complex resists RNA denaturants and chelation by EDTA. While the Ni(II) version of the complex is rapidly destroyed by gentle heating, the Pt(II) version is stable for several hours at 50°C. We are unaware of other published accounts of Ni(II)- or Pt(II)-mediated substrate binding by RNA. These metals could facilitate assembly of other complex structures, and they could be exploited in future selections for ribozyme activity. There are many applications for which it would be desirable to regulate ribozyme activity by means of an extrinsic factor, including controlled cleavage of mRNA or viral RNA inside cells and analyte detection on microarray chips. In the "TRAP" design (Targeted Ribozyme Attenuated Probes), a 3' terminal "attenuator" anneals to conserved bases in the catalytic core of the hammerhead ribozyme to form the "off" state. Binding of RNA or DNA to an antisense sequence linking the ribozyme and attenuator frees the core to fold into an active conformation. Because the antisense does not directly interfere with the ribozyme, the system can be programmed to be activated by virtually any accessible RNA sequence. Attenuated hammerhead ribozymes were shown to be activated 250- to 1760-fold upon addition of various oligonucleotide strands. RNA oligonucleotides were more effective activators than DNA oligos, consistent with known relative helix stabilities of RNA-RNA > RNA-DNA. |
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Nakanishi Prize
2:00 PM-4:40 PM, Wednesday, March 26, 2003 Convention Center -- La Nouvelle Ballroom A/B, Oral
Division of Organic Chemistry |