1za7

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The crystal structure of salt stable cowpea cholorotic mottle virus at 2.7 angstroms resolution.The crystal structure of salt stable cowpea cholorotic mottle virus at 2.7 angstroms resolution.

Structural highlights

1za7 is a 3 chain structure with sequence from Cowpea chlorotic mottle virus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.7Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CAPSD_CCMV Capsid protein. Probably binds RNA and plays a role in packaging.[1]

Publication Abstract from PubMed

Structural transitions in viral capsids play a critical role in the virus life cycle, including assembly, disassembly, and release of the packaged nucleic acid. Cowpea chlorotic mottle virus (CCMV) undergoes a well-studied reversible structural expansion in vitro in which the capsid expands by 10%. The swollen form of the particle can be completely disassembled by increasing the salt concentration to 1 M. Remarkably, a single-residue mutant of the CCMV N-terminal arm, K42R, is not susceptible to dissociation in high salt (salt-stable CCMV [SS-CCMV]) and retains 70% of wild-type infectivity. We present the combined structural and biophysical basis for the chemical stability and viability of the SS-CCMV particles. A 2.7-A resolution crystal structure of the SS-CCMV capsid shows an addition of 660 new intersubunit interactions per particle at the center of the 20 hexameric capsomeres, which are a direct result of the K42R mutation. Protease-based mapping experiments of intact particles demonstrate that both the swollen and closed forms of the wild-type and SS-CCMV particles have highly dynamic N-terminal regions, yet the SS-CCMV particles are more resistant to degradation. Thus, the increase in SS-CCMV particle stability is a result of concentrated tethering of subunits at a local symmetry interface (i.e., quasi-sixfold axes) that does not interfere with the function of other key symmetry interfaces (i.e., fivefold, twofold, quasi-threefold axes). The result is a particle that is still dynamic but insensitive to high salt due to a new series of bonds that are resistant to high ionic strength and preserve the overall particle structure.

Enhanced local symmetry interactions globally stabilize a mutant virus capsid that maintains infectivity and capsid dynamics.,Speir JA, Bothner B, Qu C, Willits DA, Young MJ, Johnson JE J Virol. 2006 Apr;80(7):3582-91. PMID:16537626[2]

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

See Also

References

  1. Annamalai P, Apte S, Wilkens S, Rao AL. Deletion of highly conserved arginine-rich RNA binding motif in cowpea chlorotic mottle virus capsid protein results in virion structural alterations and RNA packaging constraints. J Virol. 2005 Mar;79(6):3277-88. PMID:15731222 doi:http://dx.doi.org/79/6/3277
  2. Speir JA, Bothner B, Qu C, Willits DA, Young MJ, Johnson JE. Enhanced local symmetry interactions globally stabilize a mutant virus capsid that maintains infectivity and capsid dynamics. J Virol. 2006 Apr;80(7):3582-91. PMID:16537626 doi:80/7/3582

1za7, resolution 2.70Å

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