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Unwinding of a DNA replication fork by a hexameric viral helicase
DOI:
10.1038/s41467-021-25843-6
Authors:
Abid
Javed
(Birkbeck College)
,
Balazs
Major
(University of Sheffield)
,
Jonathan A.
Stead
(University of Sheffield)
,
Cyril M.
Sanders
(University of Sheffield)
,
Elena V.
Orlova
(Birkbeck College)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Nature Communications
, VOL 12
State:
Published (Approved)
Published:
September 2021
Diamond Proposal Number(s):
14704

Abstract: Hexameric helicases are motor proteins that unwind double-stranded DNA (dsDNA) during DNA replication but how they are optimised for strand separation is unclear. Here we present the cryo-EM structure of the full-length E1 helicase from papillomavirus, revealing all arms of a bound DNA replication fork and their interactions with the helicase. The replication fork junction is located at the entrance to the helicase collar ring, that sits above the AAA + motor assembly. dsDNA is escorted to and the 5´ single-stranded DNA (ssDNA) away from the unwinding point by the E1 dsDNA origin binding domains. The 3´ ssDNA interacts with six spirally-arranged β-hairpins and their cyclical top-to-bottom movement pulls the ssDNA through the helicase. Pulling of the RF against the collar ring separates the base-pairs, while modelling of the conformational cycle suggest an accompanying movement of the collar ring has an auxiliary role, helping to make efficient use of ATP in duplex unwinding.
Journal Keywords: DNA replication; Electron microscopy; Origin selection; Structural biology
Diamond Keywords: Viruses
Subject Areas:
Biology and Bio-materials
Diamond Offline Facilities:
Electron Bio-Imaging Centre (eBIC)
Instruments:
Krios I-Titan Krios I at Diamond
Added On:
27/09/2021 10:33
Documents:
s41467-021-25843-6.pdf
Discipline Tags:
Pathogens
Infectious Diseases
Health & Wellbeing
Structural biology
Life Sciences & Biotech
Technical Tags:
Microscopy
Electron Microscopy (EM)
Cryo Electron Microscopy (Cryo EM)