6w7t

Structure of PaP3 small terminase

spinqualitylabelsall models 6w7t, resolution 3.01Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6w7t is a 9 chain structure with sequence from Pseudomonas virus PaP3. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.01Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8H9R5_9CAUD Publication Abstract from PubMed The genome packaging motor of tailed bacteriophages and herpesviruses is a powerful nanomachine built by several copies of a large (TerL) and a small (TerS) terminase subunit. The motor assembles transiently at the portal vertex of an empty precursor capsid (or procapsid) to power genome encapsidation. Terminase subunits have been studied in-depth, especially in classical bacteriophages that infect Escherichia coli or Salmonella, yet, less is known about the packaging motor of Pseudomonas-phages that have increasing biomedical relevance. Here, we investigated the small terminase subunit from three Podoviridae phages that infect Pseudomonas aeruginosa. We found TerS is polymorphic in solution but assembles into a nonamer in its high-affinity heparin-binding conformation. The atomic structure of Pseudomonas phage PaP3 TerS, the first complete structure for a TerS from a cos phage, reveals nine helix-turn-helix (HTH) motifs asymmetrically arranged around a beta-stranded channel, too narrow to accommodate DNA. PaP3 TerS binds DNA in a sequence-specific manner in vitro. X-ray scattering and molecular modeling suggest TerS adopts an open conformation in solution, characterized by dynamic HTHs that move around an oligomerization core, generating discrete binding crevices for DNA. We propose a model for sequence-specific recognition of packaging initiation sites by lateral interdigitation of DNA. Biophysical analysis of Pseudomonas-phage PaP3 small terminase suggests a mechanism for sequence-specific DNA-binding by lateral interdigitation.,Niazi M, Florio TJ, Yang R, Lokareddy RK, Swanson NA, Gillilan RE, Cingolani G Nucleic Acids Res. 2020 Oct 30. pii: 5943822. doi: 10.1093/nar/gkaa866. PMID:33125059 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Terminase 3D Structures

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