1nyi

Crosslinked Hammerhead Ribozyme Initial State

spinqualitylabelsall models 1nyi, resolution 2.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nyi is a 2 chain structure with sequence from Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.85Å Ligands: 5GP, CO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed We have captured the structure of a pre-catalytic conformational intermediate of the hammerhead ribozyme using a phosphodiester tether formed between I and Stem II. This phosphodiester tether appears to mimic interactions in the wild-type hammerhead RNA that enable switching between nuclease and ligase activities, both of which are required in the replicative cycles of the satellite RNA viruses from which the hammerhead ribozyme is derived. The structure of this conformational intermediate reveals how the attacking nucleophile is positioned prior to cleavage, and demonstrates how restricting the ability of Stem I to rotate about its helical axis, via interactions with Stem II, can inhibit cleavage. Analogous covalent crosslinking experiments have demonstrated that imposing such restrictions on interhelical movement can change the hammerhead ribozyme from a nuclease to a ligase. Taken together, these results permit us to suggest that switching between ligase and nuclease activity is determined by the helical orientation of Stem I relative to Stem II. A helical twist-induced conformational switch activates cleavage in the hammerhead ribozyme.,Dunham CM, Murray JB, Scott WG J Mol Biol. 2003 Sep 12;332(2):327-36. PMID:12948485 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribozyme 3D structures

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