1za7
From Proteopedia
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The crystal structure of salt stable cowpea cholorotic mottle virus at 2.7 angstroms resolution.
Overview
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.
About this Structure
1ZA7 is a Single protein structure of sequence from Cowpea chlorotic mottle virus. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Wed Nov 21 07:20:18 2007
Categories: Cowpea chlorotic mottle virus | Single protein | Bothner, B. | Johnson, J.E. | Qu, C. | Speir, J.A. | Willits, D.A. | Young, M.J. | Beta barrel | Beta hexamer | Bromovirus | Icosahedral particle | Icosahedral virus | Mutant virus capsid structure | Point mutation | Stable mutant | Stablizing mutation
