3zqq

Crystal structure of the full-length small terminase from a SPP1-like bacteriophage

spinqualitylabelsall models 3zqq, resolution 4.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3zqq is a 3 chain structure with sequence from Bacillus phage SF6. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 4Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TERS_BPSF6 Publication Abstract from PubMed Genome packaging into preformed viral procapsids is driven by powerful molecular motors. The small terminase protein is essential for the initial recognition of viral DNA and regulates the motor's ATPase and nuclease activities during DNA translocation. The crystal structure of a full-length small terminase protein from the Siphoviridae bacteriophage SF6, comprising the N-terminal DNA binding, the oligomerization core, and the C-terminal beta-barrel domains, reveals a nine-subunit circular assembly in which the DNA-binding domains are arranged around the oligomerization core in a highly flexible manner. Mass spectrometry analysis and four further crystal structures show that, although the full-length protein exclusively forms nine-subunit assemblies, protein constructs missing the C-terminal beta-barrel form both nine-subunit and ten-subunit assemblies, indicating the importance of the C terminus for defining the oligomeric state. The mechanism by which a ring-shaped small terminase oligomer binds viral DNA has not previously been elucidated. Here, we probed binding in vitro by using EPR and surface plasmon resonance experiments, which indicated that interaction with DNA is mediated exclusively by the DNA-binding domains and suggested a nucleosome-like model in which DNA binds around the outside of the protein oligomer. Structural basis for DNA recognition and loading into a viral packaging motor.,Buttner CR, Chechik M, Ortiz-Lombardia M, Smits C, Ebong IO, Chechik V, Jeschke G, Dykeman E, Benini S, Robinson CV, Alonso JC, Antson AA Proc Natl Acad Sci U S A. 2011 Dec 29. PMID:22207627 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Terminase 3D Structures

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