3nt7

Crystal Structure of Vaccinia Virus Uracil DNA Glycosylase R187V Mutant

spinqualitylabelsall models 3nt7, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3nt7 is a 2 chain structure with sequence from Vaccinia virus Western Reserve. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Ligands: GOL, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function UNG_VACCW Excises uracil residues from the DNA which can arise as a result of misincorporation of dUMP residues by DNA polymerase or due to deamination of cytosine. Also part of a heterodimeric processivity factor which potentiates the DNA polymerase activity. Binds to DNA (By similarity). Publication Abstract from PubMed Genome replication is inefficient without processivity factors, which tether DNA polymerases to their templates. The vaccinia virus DNA polymerase E9 requires two viral proteins, A20 and D4, for processive DNA synthesis, yet the mechanism of how this tricomplex functions is unknown. This study confirms that these three proteins are necessary and sufficient for processivity, and it focuses on the role of D4, which also functions as a uracil DNA glycosylase (UDG) repair enzyme. A series of D4 mutants was generated to discover which sites are important for processivity. Three point mutants (K126V, K160V, and R187V) which did not function in processive DNA synthesis, though they retained UDG catalytic activity, were identified. The mutants were able to compete with wild-type D4 in processivity assays and retained binding to both A20 and DNA. The crystal structure of R187V was resolved and revealed that the local charge distribution around the substituted residue is altered. However, the mutant protein was shown to have no major structural distortions. This suggests that the positive charges of residues 126, 160, and 187 are required for D4 to function in processive DNA synthesis. Consistent with this is the ability of the conserved mutant K126R to function in processivity. These mutants may help unlock the mechanism by which D4 contributes to processive DNA synthesis. Vaccinia virus D4 mutants defective in processive DNA synthesis retain binding to A20 and DNA.,Druck Shudofsky AM, Silverman JE, Chattopadhyay D, Ricciardi RP J Virol. 2010 Dec;84(23):12325-35. Epub 2010 Sep 22. PMID:20861259 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA glycosylase 3D structures

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