3r3l
From Proteopedia
Structure of NP protein from Lassa AV strain
Structural highlights
FunctionQ9DQX7_LASV Encapsidates the genome, protecting it from nucleases. The encapsidated genomic RNA is termed the nucleocapsid (NC). Serves as template for viral transcription and replication. The increased presence of protein N in host cell does not seem to trigger the switch from transcription to replication as observed in other negative strain RNA viruses. Through the interaction with host IKBKE, strongly inhibits the phosphorylation and nuclear translocation of host IRF3, a protein involved in interferon activation pathway, leading to the inhibition of interferon-beta and IRF3-dependent promoters activation. Encodes also a functional 3'-5' exoribonuclease that degrades preferentially dsRNA substrates and therby participates in the suppression of interferon induction.[HAMAP-Rule:MF_04085] Publication Abstract from PubMedThe nucleoprotein (NP) of Lassa virus (LASV) strain AV was expressed in a recombinant baculovirus system. The crystal structure of full-length NP was solved at a resolution of 2.45 A. The overall fold corresponds to that of NP of LASV strain Josiah (Qi, X., Lan, S., Wang, W., Schelde, L. M., Dong, H., Wallat, G. D., Ly, H., Liang, Y., and Dong, C. (2010) Nature 468, 779-783) with a root mean square deviation of 0.67 A for all atoms (6.3% difference in primary sequence). As the packing in the crystal offers two different trimer architectures for the biological assembly, the quaternary structure of NP in solution was determined by small-angle x-ray scattering and EM. After classification and averaging of >6000 EM raw images, trimeric centrosymmetric structures were obtained, which correspond in size and shape to one trimer in the crystal structure formed around a crystallographic 3-fold rotation axis (symmetric trimer). The symmetric trimer is also a good model for the small-angle x-ray scattering data and could be well embedded into the ab initio model. The N-terminal domain of NP contains a deep nucleotide-binding cavity that has been proposed to bind cellular cap structures for priming viral mRNA synthesis. All residues implicated in m(7)GpppN binding were exchanged, and the transcription/replication phenotype of the NP mutant was tested using a LASV replicon system. None of the mutants showed a specific defect in mRNA expression; most were globally defective in RNA synthesis. In conclusion, we describe the full-length crystal structure and the quaternary structure in solution of LASV NP. The nucleotide-binding pocket of NP could not be assigned a specific role in viral mRNA synthesis. Structure of the Lassa virus nucleoprotein revealed by X-ray crystallography, small-angle X-ray scattering, and electron microscopy.,Brunotte L, Kerber R, Shang W, Hauer F, Hass M, Gabriel M, Lelke M, Busch C, Stark H, Svergun DI, Betzel C, Perbandt M, Gunther S J Biol Chem. 2011 Nov 4;286(44):38748-56. Epub 2011 Sep 14. PMID:21917929[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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