View source for 4bbl


==Cryo-electron microscopy reconstruction of the helical part of influenza A virus ribonucleoprotein isolated from virions.==
<SX load='4bbl' size='340' side='right' viewer='molstar' caption='[[4bbl]], [[Resolution|resolution]] 18.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4bbl]] is a 26 chain structure with sequence from [https://en.wikipedia.org/wiki/Influenza_A_virus Influenza A virus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4BBL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4BBL 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]] 18&#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=4bbl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4bbl OCA], [https://pdbe.org/4bbl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4bbl RCSB], [https://www.ebi.ac.uk/pdbsum/4bbl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4bbl ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/Q1K9H2_I33A0 Q1K9H2_I33A0] 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 ==
The influenza viruses cause annual epidemics of respiratory disease and occasional pandemics, which constitute a major public-health issue. The segmented negative-stranded RNAs are associated with the polymerase complex and nucleoprotein (NP), forming ribonucleoproteins (RNPs), which are responsible for virus transcription and replication. We describe the structure of native RNPs derived from virions. They show a double-helical conformation in which two NP strands of opposite polarity are associated with each other along the helix. Both strands are connected by a short loop at one end of the particle and interact with the polymerase complex at the other end. This structure will be relevant for unraveling the mechanisms of nuclear import of parental virus RNPs, their transcription and replication, and the encapsidation of progeny RNPs into virions.

The structure of native influenza virion ribonucleoproteins.,Arranz R, Coloma R, Chichon FJ, Conesa JJ, Carrascosa JL, Valpuesta JM, Ortin J, Martin-Benito J Science. 2012 Dec 21;338(6114):1634-7. doi: 10.1126/science.1228172. Epub 2012, Nov 22. PMID:23180776<ref>PMID:23180776</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4bbl" style="background-color:#fffaf0;"></div>

==See Also==
*[[Nucleoprotein 3D structures|Nucleoprotein 3D structures]]
== References ==
<references/>
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[[Category: Influenza A virus]]
[[Category: Large Structures]]
[[Category: Arranz R]]
[[Category: Carrascosa JL]]
[[Category: Chichon FJ]]
[[Category: Coloma R]]
[[Category: Conesa JJ]]
[[Category: Martin-Benito J]]
[[Category: Ortin J]]
[[Category: Valpuesta JM]]