View source for 4tu0


==CRYSTAL STRUCTURE OF CHIKUNGUNYA VIRUS NSP3 MACRO DOMAIN IN COMPLEX WITH A 2'-5' OLIGOADENYLATE TRIMER==
<StructureSection load='4tu0' size='340' side='right'caption='[[4tu0]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4tu0]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Chikungunya_virus Chikungunya virus] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4TU0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4TU0 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene></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=4tu0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4tu0 OCA], [https://pdbe.org/4tu0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4tu0 RCSB], [https://www.ebi.ac.uk/pdbsum/4tu0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4tu0 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/POLN_CHIKS POLN_CHIKS] P123 is short-lived polyproteins, accumulating during early stage of infection. It localizes the viral replication complex to the cytoplasmic surface of modified endosomes and lysosomes. By interacting with nsP4, it starts viral genome replication into antigenome. After these early events, P123 is cleaved sequentially into nsP1, nsP2 and nsP3. This sequence of delayed processing would allow correct assembly and membrane association of the RNA polymerase complex (By similarity).  nsP1 is a cytoplasmic capping enzyme. This function is necessary since all viral RNAs are synthesized in the cytoplasm, and host capping enzymes are restricted to the nucleus. The enzymatic reaction involves a covalent link between 7-methyl-GMP and nsP1, whereas eukaryotic capping enzymes form a covalent complex only with GMP. nsP1 capping would consist in the following reactions: GTP is first methylated and then forms the m7GMp-nsP1 complex, from which 7-methyl-GMP complex is transferred to the mRNA to create the cap structure. Palmitoylated nsP1 is remodeling host cell cytoskeleton, and induces filopodium-like structure formation at the surface of the host cell (By similarity).  nsP2 has two separate domain with different biological activities. The N-terminal section is part of the RNA polymerase complex and has RNA trisphosphatase and RNA helicase activity. The C-terminal section harbors a protease that specifically cleaves and releases the four mature proteins (By similarity). Also inhibits cellular transcription by inducing rapid degradation of POLR2A, a catalytic subunit of the RNAPII complex. The resulting inhibition of cellular protein synthesis serves to ensure maximal viral gene expression and to evade host immune response.  nsP3 is essential for minus strand and subgenomic 26S mRNA synthesis (By similarity).  nsP4 is an RNA dependent RNA polymerase. It replicates genomic and antigenomic RNA by recognizing replications specific signals. Transcribes also a 26S subgenomic mRNA by initiating RNA synthesis internally on antigenomic RNA. This 26S mRNA codes for structural proteins (By similarity).
__TOC__
</StructureSection>
[[Category: Chikungunya virus]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Canard b]]
[[Category: Coutard b]]
[[Category: Ferron fp]]
[[Category: Malet h]]
[[Category: Morin B]]