Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Biochemical and structural basis of Dicer helicase function unveiled by resurrecting ancient proteins.
Journal, issue, pages	Proc Natl Acad Sci U S A, Vol. 122, Issue 22, Page e2500825122, Year 2025
Publish date	Jun 3, 2025
Authors	Adedeji M Aderounmu / Josephine Maus-Conn / Claudia D Consalvo / Peter S Shen / Brenda L Bass /
PubMed Abstract	A fully functional Dicer helicase, present in the modern arthropod, uses energy from ATP hydrolysis to power translocation on bound dsRNA, enabling the processive dsRNA cleavage required for ...A fully functional Dicer helicase, present in the modern arthropod, uses energy from ATP hydrolysis to power translocation on bound dsRNA, enabling the processive dsRNA cleavage required for efficient antiviral defense. However, modern Dicer orthologs exhibit divergent helicase functions that affect their ability to contribute to antiviral defense. Moreover, mechanisms that couple ATP hydrolysis to Dicer helicase movement on dsRNA remain enigmatic. We used biochemical and structural analyses of ancestrally reconstructed Dicer helicases to map evolution of dsRNA binding affinity, ATP hydrolysis and translocation. Loss of affinity for dsRNA occurred early in Dicer evolution, coinciding with a decline in translocation activity, despite preservation of ATP hydrolysis activity. Ancestral nematode Dicer also exhibited significant decline in ATP hydrolysis and translocation, but studies of antiviral activities in the modern nematode indicate Dicer retained a role in antiviral defense by recruiting a second helicase. Cryogenic electron microscopy (cryo-EM) analyses of an ancient metazoan Dicer allowed capture of multiple helicase states revealing the mechanism that connects each step of ATP hydrolysis to unidirectional movement along dsRNA. Our study rationalizes the diversity in modern Dicer helicases by connecting ancestral functions to observations in extant enzymes.
External links	Proc Natl Acad Sci U S A / PubMed:40434637 / PubMed Central
Methods	EM (single particle)
Resolution	3.0 - 3.4 Å
Structure data	48678 9mw6 EMDB-48678, PDB-9mw6: Cryo-EM structure of ancestral Dicer helicase bound to 27-bp dsRNA Method: EM (single particle) / Resolution: 3.4 Å 48691 9mw7 EMDB-48691, PDB-9mw7: Cryo-EM structure of ancestral Dicer helicase bound to 27-bp dsRNA in end-bound transition state Method: EM (single particle) / Resolution: 3.4 Å 48697 9mw8 EMDB-48697, PDB-9mw8: Cryo-EM structure of ancestral Dicer helicase bound to 27-bp dsRNA in post-hydrolysis closed state Method: EM (single particle) / Resolution: 3.3 Å 48708 9mx3 EMDB-48708, PDB-9mx3: Cryo-EM structure of ancestral Dicer helicase bound to 27-bp dsRNA in post-hydrolysis semi-closed state Method: EM (single particle) / Resolution: 3.0 Å 48710 9mx5 EMDB-48710, PDB-9mx5: Cryo-EM structure of ancestral Dicer helicase bound to 27-bp dsRNA in internally-bound transition state Method: EM (single particle) / Resolution: 3.1 Å
Chemicals	ChemComp-AF3: ALUMINUM FLUORIDE ChemComp-ADP: ADENOSINE-5'-DIPHOSPHATE / ADP, energy-carrying moleculeYM ChemComp-MG*: Unknown entry
Source	synthetic construct (others)
Keywords	ANTIVIRAL PROTEIN/RNA / RNA helicase / dsRBM / ANTIVIRAL PROTEIN-RNA complex