Structural highlights
Function
A20_VACCC Plays an essential role in viral DNA replication by acting as the polymerase processivity factor together with protein D4. May serve as a bridge which links the DNA polymerase E9 and the uracil DNA glycosylase (By similarity).DPOL_VAR67 Catalyzes DNA synthesis. Acquires processivity by associating with a heterodimeric processivity factor comprised of the viral OPG148 and OPG116 proteins, thereby forming the DNA polymerase holoenzyme. Displays 3'- to 5' exonuclease activity. Might participate in viral DNA recombination. Does not perform OPG116/D4synthesis across an abasic site.[UniProtKB:P06856]
Publication Abstract from PubMed
Poxviruses are enveloped viruses with a linear, double-stranded DNA genome. Viral DNA synthesis is achieved by a functional DNA polymerase holoenzyme composed of three essential proteins. For vaccinia virus (VACV) these are E9, the catalytic subunit, a family B DNA polymerase, and the heterodimeric processivity factor formed by D4 and A20. The A20 protein links D4 to the catalytic subunit. High-resolution structures have been obtained for the VACV D4 protein in complex with an N-terminal fragment of A20 as well as for E9. In addition, biochemical studies provided evidence that a poxvirus-specific insertion (insert 3) in E9 interacts with the C-terminal residues of A20. Here, we provide solution structures of two different VACV A20 C-terminal constructs containing residues 304-426, fused at their C-terminus to either a BAP (Biotin Acceptor Peptide)-tag or a short peptide containing the helix of E9 insert 3. Together with results from titration studies, these structures shed light on the molecular interface between the catalytic subunit and the processivity factor component A20. The interface comprises hydrophobic residues conserved within the Chordopoxvirinae subfamily. Finally, we constructed a HADDOCK model of the VACV A20304-426-E9 complex, which is in excellent accordance with previous experimental data.
Solution Structure of the C-terminal Domain of A20, the Missing Brick for the Characterization of the Interface between Vaccinia Virus DNA Polymerase and its Processivity Factor.,Bersch B, Tarbouriech N, Burmeister WP, Iseni F J Mol Biol. 2021 Apr 24;433(13):167009. doi: 10.1016/j.jmb.2021.167009. PMID:33901538[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Bersch B, Tarbouriech N, Burmeister WP, Iseni F. Solution Structure of the C-terminal Domain of A20, the Missing Brick for the Characterization of the Interface between Vaccinia Virus DNA Polymerase and its Processivity Factor. J Mol Biol. 2021 Apr 24;433(13):167009. doi: 10.1016/j.jmb.2021.167009. PMID:33901538 doi:http://dx.doi.org/10.1016/j.jmb.2021.167009
