Three-dimensional structure of a hammerhead ribozyme.

H W Pley; K M Flaherty; D B McKay

doi:10.1038/372068a0

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Three-dimensional structure of a hammerhead ribozyme.

H W Pley·K M Flaherty·D B McKay

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Abstract

The hammerhead ribozyme is a small catalytic RNA motif made up of three base-paired stems and a core of highly conserved, non-complementary nucleotides essential for catalysis. The X-ray crystallographic structure of a hammerhead RNA-DNA ribozyme-inhibitor complex at 2.6 A resolution reveals that the base-paired stems are A-form helices and that the core has two structural domains. The first domain is formed by the sequence 5'-CUGA following stem I and is a sharp turn identical to the uridine turn of transfer RNA, whereas the second is a non-Watson-Crick three-base-pair duplex with a divalent-ion binding site. The phosphodiester backbone of the DNA inhibitor strand is splayed out at the phosphate 5' to the cleavage site. The structure indicates that the ribozyme may destabilize a substrate strand in order to facilitate twisting of the substrate to allow cleavage of the scissile bond.

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Base Sequence Binding Sites Crystallography, X-Ray DNA Models, Molecular Molecular Sequence Data Nucleic Acid Conformation RNA, Catalytic Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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H W Pley, K M Flaherty, D B McKay. 1994-11-03. Three-dimensional structure of a hammerhead ribozyme.. https://doi.org/10.1038/372068a0

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