TY  - JOUR
A1  - Hutin, Stephanie
A1  - Ling, Wai Li
A1  - Tarbouriech, Nicolas
A1  - Schoehn, Guy
A1  - Grimm, Clemens
A1  - Fischer, Utz
A1  - Burmeister, Wim P.
T1  - The vaccinia virus DNA helicase structure from combined single-particle cryo-electron microscopy and AlphaFold2 prediction
JF  - Viruses
N2  - Poxviruses are large DNA viruses with a linear double-stranded DNA genome circularized at the extremities. The helicase-primase D5, composed of six identical 90 kDa subunits, is required for DNA replication. D5 consists of a primase fragment flexibly attached to the hexameric C-terminal polypeptide (res. 323–785) with confirmed nucleotide hydrolase and DNA-binding activity but an elusive helicase activity. We determined its structure by single-particle cryo-electron microscopy. It displays an AAA+ helicase core flanked by N- and C-terminal domains. Model building was greatly helped by the predicted structure of D5 using AlphaFold2. The 3.9 Å structure of the N-terminal domain forms a well-defined tight ring while the resolution decreases towards the C-terminus, still allowing the fit of the predicted structure. The N-terminal domain is partially present in papillomavirus E1 and polyomavirus LTA helicases, as well as in a bacteriophage NrS-1 helicase domain, which is also closely related to the AAA+ helicase domain of D5. Using the Pfam domain database, a D5_N domain followed by DUF5906 and Pox_D5 domains could be assigned to the cryo-EM structure, providing the first 3D structures for D5_N and Pox_D5 domains. The same domain organization has been identified in a family of putative helicases from large DNA viruses, bacteriophages, and selfish DNA elements.
KW  - DNA replication
KW  - helicase
KW  - Pfam domain
KW  - poxvirus
KW  - cryo-electron microscopy
KW  - structure prediction
KW  - SF3 helicase
KW  - orthopoxvirus
KW  - DNA helicase
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290523
SN  - 1999-4915
VL  - 14
IS  - 10
ER  -