A phosphate-binding pocket within the platform-PAZ-connector helix cassette of human Dicer.
Mol Cell
; 53(4): 606-16, 2014 Feb 20.
Article
in En
| MEDLINE
| ID: mdl-24486018
ABSTRACT
We have solved two families of crystal structures of the human Dicer "platform-PAZ-connector helix" cassette in complex with small interfering RNAs (siRNAs). The structures possess two adjacently positioned pockets a 2 nt 3'-overhang-binding pocket within the PAZ domain (3' pocket) and a phosphate-binding pocket within the platform domain (phosphate pocket). One family of complexes contains a knob-like α-helical protrusion, designated "hDicer-specific helix," that separates the two pockets and orients the bound siRNA away from the surface of Dicer, which could be indicative of a product release/transfer state. In the second complex, the helical protrusion is melted/disordered and the bound siRNA is aligned toward the surface of Dicer, suggestive of a cleavage-competent state. These structures allow us to propose that the transition from the cleavage-competent to the postulated product release/transfer state may involve release of the 5'-phosphate from the phosphate pocket while retaining the 3' overhang in the 3' pocket.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ribonuclease III
/
DEAD-box RNA Helicases
Limits:
Animals
/
Humans
Language:
En
Journal:
Mol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2014
Type:
Article
Affiliation country:
United States