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6sag

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Cryo-EM structure of TMV with Ca2+ at low pH

6sag, resolution 2.00Å

Structural highlights

6sag is a 2 chain structure with sequence from Tobacco mosaic virus (vulgare). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 2Å
Ligands:
Experimental data:	Check to display Experimental Data
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CAPSD_TMV Capsid protein self-assembles to form rod-shaped virions about 18 nm in diameter with a central canal enclosing the viral genomic RNA.

Publication Abstract from PubMed

Stable capsid structures of viruses protect viral RNA while they also require controlled disassembly for releasing the viral genome in the host cell. A detailed understanding of viral disassembly processes and the involved structural switches is still lacking. This process has been extensively studied using tobacco mosaic virus (TMV), and carboxylate interactions are assumed to play a critical part in this process. Here, we present two cryo-EM structures of the helical TMV assembly at 2.0 and 1.9 A resolution in conditions of high Ca(2+) concentration at low pH and in water. Based on our atomic models, we identify the conformational details of the disassembly switch mechanism: In high Ca(2+) /acidic pH environment, the virion is stabilized between neighboring subunits through carboxyl groups E95 and E97 in close proximity to a Ca(2+) binding site that is shared between two subunits. Upon increase in pH and lower Ca(2+) levels, mutual repulsion of the E95/E97 pair and Ca(2+) removal destabilize the network of interactions between adjacent subunits at lower radius and release the switch for viral disassembly.

Elucidation of the viral disassembly switch of tobacco mosaic virus.,Weis F, Beckers M, von der Hocht I, Sachse C EMBO Rep. 2019 Nov 5;20(11):e48451. doi: 10.15252/embr.201948451. Epub 2019 Sep, 19. PMID:31535454^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Weis F, Beckers M, von der Hocht I, Sachse C. Elucidation of the viral disassembly switch of tobacco mosaic virus. EMBO Rep. 2019 Nov 5;20(11):e48451. doi: 10.15252/embr.201948451. Epub 2019 Sep, 19. PMID:31535454 doi:http://dx.doi.org/10.15252/embr.201948451