6BU9

Drosophila Dicer-2 bound to blunt dsRNA

Summary for 6BU9

• Entry DOI: 10.2210/pdb6bu9/pdb
• EMDB information: 7290 7291
• Descriptor: Dicer-2, isoform A, RNA (5'-R(*GP*GP*AP*GP*GP*UP*AP*GP*UP*AP*GP*GP*UP*UP*GP*UP*AP*UP*AP*GP*UP*AP*GP*U)-3'), RNA (5'-R(*AP*CP*UP*AP*CP*UP*AP*UP*AP*CP*AP*AP*CP*CP*UP*AP*C)-3') (3 entities in total)
• Functional Keywords: dicer, dcr2, dcr-2, dmdcr-2, dicer-2, helicase, dsrna, rna, rna binding protein, rna binding protein-rna complex, rna binding protein/rna
• Biological source: Drosophila melanogaster (Fruit fly); More
• Total number of polymer chains: 3
• Total formula weight: 231384.59

Authors

Shen, P.S.,Sinha, N.K.,Bass, B.L. (deposition date: 2017-12-09, release date: 2017-12-27, Last modification date: 2024-03-13)

Primary citation

Sinha, N.K.,Iwasa, J.,Shen, P.S.,Bass, B.L.
Dicer uses distinct modules for recognizing dsRNA termini.
Science, 359:329-334, 2018

PubMed Abstract: Invertebrates rely on Dicer to cleave viral double-stranded RNA (dsRNA), and Dicer-2 distinguishes dsRNA substrates by their termini. Blunt termini promote processive cleavage, while 3' overhanging termini are cleaved distributively. To understand this discrimination, we used cryo-electron microscopy to solve structures of Dicer-2 alone and in complex with blunt dsRNA. Whereas the Platform-PAZ domains have been considered the only Dicer domains that bind dsRNA termini, unexpectedly, we found that the helicase domain is required for binding blunt, but not 3' overhanging, termini. We further showed that blunt dsRNA is locally unwound and threaded through the helicase domain in an adenosine triphosphate-dependent manner. Our studies reveal a previously unrecognized mechanism for optimizing antiviral defense and set the stage for the discovery of helicase-dependent functions in other Dicers.

PubMed: 29269422
DOI: 10.1126/science.aaq0921

Experimental method

ELECTRON MICROSCOPY (6.8 Å)