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==Crystal Structure of Influenza B Virus Nucleoprotein==
<StructureSection load='3tj0' size='340' side='right'caption='[[3tj0]], [[Resolution|resolution]] 3.23&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3tj0]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Influenza_B_virus_(B/Managua/4577.01/2008) Influenza B virus (B/Managua/4577.01/2008)]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3TJ0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3TJ0 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.233&#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=3tj0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3tj0 OCA], [https://pdbe.org/3tj0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3tj0 RCSB], [https://www.ebi.ac.uk/pdbsum/3tj0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3tj0 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/C4LQ26_9INFB C4LQ26_9INFB] Encapsidates the negative strand viral RNA, protecting it from nucleases. The encapsidated genomic RNA is termed the ribonucleoprotein (RNP) and serves as template for transcription and replication. The RNP needs to be localized in the nucleus to start an infectious cycle, but is too large to diffuse through the nuclear pore complex. NP comprises at least 2 nuclear localization signals and is responsible of the active RNP import into the nucleus through the cellular importin alpha/beta pathway. Later in the infection, nucleus export of RNP are mediated through viral proteins NEP interacting with M1 which binds nucleoproteins. It is possible that the nucleoprotein binds directly exportin-1 (XPO1) and plays an active role in RNP nuclear export. M1 interaction with RNP seems to hide nucleoprotein's nuclear localization signals. Soon after a virion infects a new cell, M1 dissociates from the RNP under acidification of the virion driven by M2 protein. Dissociation of M1 from RNP unmask nucleoprotein's nuclear localization signals, targeting the RNP to the nucleus (By similarity).[SAAS:SAAS002141_004_603280]
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== Publication Abstract from PubMed ==
Influenza virus nucleoprotein (NP) is the major component of the viral ribonucleoprotein complex, which is crucial for the transcription and replication of the viral genome. We have determined the crystal structure of influenza B virus NP to a resolution of 3.2 A. Influenza B NP contains a head, a body domain, and a tail loop. The electropositive groove between the head and body domains of influenza B NP is crucial for RNA binding. This groove also contains an extended flexible charged loop (amino acids [aa] 125 to 149), and two lysine clusters at the first half of this loop were shown to be crucial for binding RNA. Influenza B virus NP forms a crystallographic homotetramer by inserting the tail loop into the body domain of the neighboring NP molecule. A deeply buried salt bridge between R472 and E395 and a hydrophobic cluster at F468 are the major driving forces for the insertion. The analysis of the influenza B virus NP structure and function and comparisons with influenza A virus NP provide insights into the mechanisms of action and underpin efforts to design inhibitors for this class of proteins.

Structural basis for RNA binding and homo-oligomer formation by influenza B virus nucleoprotein.,Ng AK, Lam MK, Zhang H, Liu J, Au SW, Chan PK, Wang J, Shaw PC J Virol. 2012 Jun;86(12):6758-67. Epub 2012 Apr 11. PMID:22496219<ref>PMID:22496219</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Nucleoprotein 3D structures|Nucleoprotein 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Au SWN]]
[[Category: Liu J]]
[[Category: Ng AKL]]
[[Category: Shaw PC]]
[[Category: Wang J]]
[[Category: Zhang H]]