Novel configurations of the hammerhead ribozyme: increased activity and reduced magnesium ion requirement.
The hammerhead ribozyme is one of the smallest of known catalytic RNAs. Its structure and mechanism have been examined using a broad range of approaches. Recently, crystal structures of the hammerhead have been reported. Within the crystal the hammerhead exists in a Y-shaped configuration in which helices I and II form the adjacent upper arms, while helix III forms the lower leg of the Y. Based on these findings, hammerheads in which helix I and II are constrained to remain adjacent and roughly parallel are expected to be catalytically active. We have examined this possibility with two novel hammerhead configurations, circular and circular/hairpin. These circular and circular/hairpin hammerhead ribozymes possess activity comparable to, and in some cases even greater than, non-constrained hammerheads. Since these novel ribozymes are constrained into a closed, and active conformation, they offer advantages for structure/function studies. Additionally, these novel ribozymes will be adventitious for antisense mediated gene inhibition, since they possess increased activity and a reduced requirement for magnesium ion, and are expected to be more resistant to nuclease degradation.
Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 421 Wakara Way, Suite 318, Salt Lake City, Utah, 84108, USA.
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Wang
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Ruffner
D002942:Circular Dichroism; D008274:Magnesium; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000737:chemistry*
D016337:RNA, Catalytic; D008274:Magnesium