Three-dimensional structure of a hammerhead ribozyme.
Pley, H.W., Flaherty, K.M., McKay, D.B.(1994) Nature 372: 68-74
- PubMed: 7969422
- DOI: https://doi.org/10.1038/372068a0
- Primary Citation of Related Structures:
1HMH - PubMed 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.
Organizational Affiliation:
Department of Structural Biology, Stanford University School of Medicine, California 94305-5400.