2nue
From Proteopedia
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Crystal structure of RNase III from Aquifex aeolicus complexed with ds-RNA at 2.9-Angstrom Resolution
Overview
RNA interference is mediated by small interfering RNAs produced by members, of the ribonuclease III (RNase III) family represented by bacterial RNase, III and eukaryotic Rnt1p, Drosha and Dicer. For mechanistic studies, bacterial RNase III has been a valuable model system for the family., Previously, we have shown that RNase III uses two catalytic sites to, create the 2-nucleotide (nt) 3' overhangs in its products. Here, we, present three crystal structures of RNase III in complex with, double-stranded RNA, demonstrating how Mg(2+) is essential for the, formation of a catalytically competent protein-RNA complex, how the use of, two Mg(2+) ions can drive the hydrolysis of each phosphodiester bond, and, how conformational changes in both the substrate and the protein are, critical elements for assembling the catalytic complex. Moreover, we have, modelled a protein-substrate complex and a protein-reaction intermediate, (transition state) complex on the basis of the crystal structures., Together, the crystal structures and the models suggest a stepwise, mechanism for RNase III to execute the phosphoryl transfer reaction.
About this Structure
2NUE is a Single protein structure of sequence from Aquifex aeolicus. Active as Ribonuclease III, with EC number 3.1.26.3 Full crystallographic information is available from OCA.
Reference
A stepwise model for double-stranded RNA processing by ribonuclease III., Gan J, Shaw G, Tropea JE, Waugh DS, Court DL, Ji X, Mol Microbiol. 2007 Dec 7;67(1):143-154. Epub 2007 Nov 27. PMID:18047582
Page seeded by OCA on Wed Jan 23 11:22:44 2008
