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1qjz
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(New page: 200px<br /><applet load="1qjz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qjz, resolution 3.8Å" /> '''THREE DIMENSIONAL STR...)
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Revision as of 22:38, 20 November 2007
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THREE DIMENSIONAL STRUCTURE OF PHYSALIS MOTTLE VIRUS: IMPLICATIONS FOR THE VIRAL ASSEMBLY
Overview
The structure of the T=3 single stranded RNA tymovirus, physalis mottle, virus (PhMV), has been determined to 3.8 A resolution. PhMV crystals, belong to the rhombohedral space group R 3, with one icosahedral particle, in the unit cell leading to 20-fold non-crystallographic redundancy., Polyalanine coordinates of the related turnip yellow mosaic virus (TYMV), with which PhMV coat protein shares 32 % amino acid sequence identity were, used for obtaining the initial phases. Extensive phase refinement by real, space molecular replacement density averaging resulted in an electron, density map that revealed density for most of the side-chains and for the, 17 residues ordered in PhMV, but not seen in TYMV, at the N terminus of, the A subunits. The core secondary and tertiary structures of the subunits, have a topology consistent with the capsid proteins of other T=3 plant, viruses. The N-terminal arms of the A subunits, which constitute 12, pentamers at the icosahedral 5-fold axes, have a conformation very, different from the conformations observed in B and C subunits that, constitute hexameric capsomers with near 6-fold symmetry at the, icosahedral 3-fold axes. An analysis of the interfacial contacts between, protein subunits indicates that the hexamers are held more strongly than, pentamers and hexamer-hexamer contacts are more extensive than, pentamer-hexamer contacts. These observations suggest a plausible, mechanism for the formation of empty capsids, which might be initiated by, a change in the conformation of the N-terminal arm of the A subunits. The, structure also provides insights into immunological and mutagenesis, results. Comparison of PhMV with the sobemovirus, sesbania mosaic virus, reveals striking similarities in the overall tertiary fold of the coat, protein although the capsid morphologies of these two viruses are very, different.
About this Structure
1QJZ is a Single protein structure of sequence from Physalis mottle virus. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of physalis mottle virus: implications for the viral assembly., Krishna SS, Hiremath CN, Munshi SK, Prahadeeswaran D, Sastri M, Savithri HS, Murthy MR, J Mol Biol. 1999 Jun 18;289(4):919-34. PMID:10369772
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