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  - 
TY  - JOUR
A1  - Veepaschit, Jyotishman
A1  - Viswanathan, Aravindan
A1  - Bordonne, Remy
A1  - Grimm, Clemens
A1  - Fischer, Utz
T1  - Identification and structural analysis of the Schizosaccharomyces pombe SMN complex
JF  - Nucleic Acids Research
N2  - The macromolecular SMN complex facilitates the formation of Sm-class ribonucleoproteins involved in mRNA processing (UsnRNPs). While biochemical studies have revealed key activities of the SMN complex, its structural investigation is lagging behind. Here we report on the identification and structural determination of the SMN complex from the lower eukaryote Schizosaccharomyces pombe, consisting of SMN, Gemin2, 6, 7, 8 and Sm proteins. The core of the SMN complex is formed by several copies of SMN tethered through its C-terminal alpha-helices arranged with alternating polarity. This creates a central platform onto which Gemin8 binds and recruits Gemins 6 and 7. The N-terminal parts of the SMN molecules extrude via flexible linkers from the core and enable binding of Gemin2 and Sm proteins. Our data identify the SMN complex as a multivalent hub where Sm proteins are collected in its periphery to allow their joining with UsnRNA.
KW  - Schizosaccharomyces pombe
KW  - SMN
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259880
VL  - 49
IS  - 13
ER  -