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 ...
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.
Related Citations:
Model for an RNA Tertiary Interaction from the Structure of an Intermolecular Complex Between a GAAA Tetraloop and an RNA Helix Pley, H.W., Flaherty, K.M., McKay, D.B. (1994) Nature 372: 111
The Crystal Structure of an All-RNA Hammerhead Ribozyme: a Proposed Mechanism for RNA Catalytic Cleavage Scott, W.G., Finch, J.T., Klug, A. (1995) Cell 81: 991
Crystals of a Hammerhead Ribozyme Pley, H.W., Lindes, D.S., Deluca-Flaherty, C., McKay, D.B. (1993) J Biol Chem 268: 19656
Organizational Affiliation:
Department of Structural Biology, Stanford University School of Medicine, California 94305-5400.
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