2eb1

From Proteopedia

Revision as of 10:21, 23 January 2008

Crystal Structure of the C-Terminal RNase III Domain of Human Dicer

Overview

Human Dicer contains two RNase III domains (RNase IIIa and RNase IIIb), that are responsible for the production of short interfering RNAs and, microRNAs. These small RNAs induce gene silencing known as RNA, interference. Here, we report the crystal structure of the C-terminal, RNase III domain (RNase IIIb) of human Dicer at 2.0 A resolution. The, structure revealed that the RNase IIIb domain can form a tightly, associated homodimer, which is similar to the dimers of the bacterial, RNase III domains and the two RNase III domains of Giardia Dicer., Biochemical analysis showed that the RNase IIIb homodimer can cleave, double-stranded RNAs (dsRNAs), and generate short dsRNAs with 2 nt 3', overhang, which is characteristic of RNase III products. The RNase IIIb, domain contained two magnesium ions per monomer around the active site., The distance between two Mg-1 ions is approximately 20.6 A, almost, identical with those observed in bacterial RNase III enzymes and Giardia, Dicer, while the locations of two Mg-2 ions were not conserved at all. We, presume that Mg-1 ions act as catalysts for dsRNA cleavage, while Mg-2, ions are involved in RNA binding.

About this Structure

2EB1 is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Ribonuclease III, with EC number 3.1.26.3 Full crystallographic information is available from OCA.

Reference

Homodimeric Structure and Double-stranded RNA Cleavage Activity of the C-terminal RNase III Domain of Human Dicer., Takeshita D, Zenno S, Lee WC, Nagata K, Saigo K, Tanokura M, J Mol Biol. 2007 Nov 16;374(1):106-20. Epub 2007 Sep 8. PMID:17920623

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