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==HK97 small terminase in complex with DNA==
<StructureSection load='8pop' size='340' side='right'caption='[[8pop]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8pop]] is a 11 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_phage_HK97 Escherichia phage HK97] and [https://en.wikipedia.org/wiki/Escherichia_virus_HK97 Escherichia virus HK97]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8POP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8POP FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8pop FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8pop OCA], [https://pdbe.org/8pop PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8pop RCSB], [https://www.ebi.ac.uk/pdbsum/8pop PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8pop ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9MBW4_BPHK7 Q9MBW4_BPHK7] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
DNA recognition is critical for assembly of double-stranded DNA viruses, in particular for the initiation of packaging the viral genome into the capsid. DNA packaging has been extensively studied for three archetypal bacteriophage systems: cos, pac and phi29. We identified the minimal site within the cos region of bacteriophage HK97 specifically recognised by the small terminase and determined a cryoEM structure for the small terminase:DNA complex. This nonameric circular protein utilizes a previously unknown mechanism of DNA binding. While DNA threads through the central tunnel, unexpectedly, DNA-recognition is generated at its exit by a substructure formed by the N- and C-terminal segments of two adjacent protomers of the terminase which are unstructured in the absence of DNA. Such interaction ensures continuous engagement of the small terminase with DNA, allowing sliding along DNA while simultaneously checking the DNA sequence. This mechanism allows locating and instigating packaging initiation and termination precisely at the cos site.

Structure of HK97 small terminase:DNA complex unveils a novel DNA binding mechanism by a circular protein.,Chechik M, Greive SJ, Antson AA, Jenkins HT bioRxiv [Preprint]. 2023 Jul 20:2023.07.17.549218. doi: , 10.1101/2023.07.17.549218. PMID:37503206<ref>PMID:37503206</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8pop" style="background-color:#fffaf0;"></div>

==See Also==
*[[Terminase 3D Structures|Terminase 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia phage HK97]]
[[Category: Escherichia virus HK97]]
[[Category: Large Structures]]
[[Category: Antson AA]]
[[Category: Chechik M]]
[[Category: Greive SJ]]
[[Category: Jenkins HT]]