6b1t: Difference between revisions
New page: {{Large structure}} ==Improved cryoEM structure of human adenovirus type 5 with atomic details of minor proteins VI and VII== <StructureSection load='6b1t' size='340' side='right' caption=... |
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Revision as of 21:08, 27 September 2017
Improved cryoEM structure of human adenovirus type 5 with atomic details of minor proteins VI and VIIImproved cryoEM structure of human adenovirus type 5 with atomic details of minor proteins VI and VII
Structural highlights
Warning: this is a large structure, and loading might take a long time or not happen at all. Function[CAP6_ADE05] Pre-protein VI: During virus assembly, promotes hexon trimers nuclear import through nuclear pore complexes via an importin alpha/beta-dependent mechanism. By analogy to herpesviruses capsid assembly, might act as a scaffold protein to promote the formation of the icosahedral capsid.[1] [2] [3] [4] [5] Endosome lysis protein: Structural component of the virion that provides increased stability to the particle shell through its interaction with the core-capsid bridging protein. Fibers shedding during virus entry into host cell allows the endosome lysis protein to be exposed as a membrane-lytic peptide. Exhibits pH-independent membrane fragmentation activity and probably mediates viral rapid escape from host endosome via organellar membrane lysis. It is not clear if it then remains partially associated with the capsid and involved in the intracellular microtubule-dependent transport of capsid to the nucleus, or if it is lost during endosomal penetration.[6] [7] [8] [9] [10] Protease cofactor: Cofactor that activates the viral protease. Binds to viral protease in a 1:1 ratio.[11] [12] [13] [14] [15] [CAP3_ADE05] Structural component of the virion that is likely to participate in vertex stabilization and genome packaging. Stabilizes vertices by tethering the penton bases to neighboring peripentonal hexons. Lashes peripentonal hexons to the neighboring hexons thanks to its interaction with hexon-linking protein. As the virus enters the host cell, capsid vertex proteins are shed concomitant with virion acidification in the endosome. During virus assembly, seems to play a role in packaging of viral DNA via its interaction with packaging protein 3.[16] [17] [NP_ADE05] Plays a role in the inhibition of host immune response within the nucleus. Interacts with cellular nucleosomes and immobilizes the host immune danger signal HMGB1 on chromatin. In turn, prevents HMGB1 release out of the cell and thus decreases inflammation. Plays also a role in the wrapping and condensation of the viral DNA. May also promote viral genome import into the nucleus.[HAMAP-Rule:MF_04056] [CAPSP_ADE05] Major capsid protein that self-associates to form penton base pentamers, each in the shape of a pentagon, situated at the 12 vertices of the pseudo T=25 capsid. Involved in virus secondary attachment to host cell after initial attachment by the fiber protein. Binds host integrin heterodimer ITGAV-ITGB5 (alphaV-beta5) thereby triggering clathrin-mediated endocytosis of virions. Mediates initial virus attachment to CXADR-negative cells. Binding to integrins ITGAV-ITGB5 also seems to induce macropinocytosis uptake of the virus. As the virus enters the host cell, penton proteins are shed concomitant with virion acidification in the endosome.[18] [19] [CAPSH_ADE05] Major capsid protein that self-associates to form 240 hexon trimers, each in the shape of a hexagon, building most of the pseudo T=25 capsid. Assembled into trimeric units with the help of the chaperone shutoff protein (By similarity). Transported by pre-protein VI to the nucleus where it associates with other structural proteins to form an empty capsid. Might be involved, through its interaction with host dyneins, in the intracellular microtubule-dependent transport of incoming viral capsid to the nucleus. [CAP8_ADE05] Hexon-linking protein: Structural component of the virion that lashes peripentonal hexons to the hexons situated in the facets thanks to its interaction with the capsid vertex protein. Also binds together hexons of different facets. [CAP9_ADE05] Structural component of the virion that presumably stabilizes the groups of hexons but is dispensable for assembly. During virus entry, recruits the anterograde motor kinesin-1 to the capsid docked at the nuclear pore complex thereby subjecting the docked capsid to a pulling force. The resulting tension leads to capsid disruption, dispersion of capsid fragments toward cell periphery and eventually viral DNA entry into the host nucleus. References
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