1ql2

Inovirus (Filamentous Bacteriophage) Strain PF1 Major Coat Protein Assembly

spinqualitylabelsall models 1ql2, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ql2 is a 3 chain structure with sequence from Pseudomonas virus Pf1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAPSD_BPPF1 Self assembles to form a helical capsid wrapping up the viral genomic DNA. The capsid displays a filamentous structure with a length of 760-1950 nm and a width of 6-8 nm. The virion assembly and budding take place at the host inner membrane (By similarity). Publication Abstract from PubMed The major coat protein in the capsid of Pf1 filamentous bacteriophage (Inovirus) forms a helical assembly of about 7000 identical protein subunits, each of which contains 46 amino-acid residues and can be closely approximated by a single gently curved alpha-helix. Since the viral DNA occupies the core of the tubular capsid and appears to make no significant specific interactions with the capsid proteins, the capsid is a simple model system for the study of the static and dynamic properties of alpha-helix assembly. The capsid undergoes a reversible temperature-induced structural transition at about 283 K between two slightly different helix forms. The two forms can coexist without an intermediate state, consistent with a first-order structural phase transition. The molecular model of the higher temperature form was refined using improved X-ray fibre diffraction data and new refinement and validation methods. The refinement indicates that the two forms are related by a change in the orientation of the capsid subunits within the virion, without a significant change in local conformation of the subunits. On the higher temperature diffraction pattern there is a region of observed intensity that is not consistent with a simple helix of identical subunits; it is proposed that the structure involves groups of three subunits which each have a slightly different orientation within the group. The grouping of subunits suggests that a change in subunit libration frequency could be the basis of the Pf1 structural transition; calculations from the model are used to explore this idea. The molecular structure and structural transition of the alpha-helical capsid in filamentous bacteriophage Pf1.,Welsh LC, Symmons MF, Marvin DA Acta Crystallogr D Biol Crystallogr. 2000 Feb;56(Pt 2):137-50. PMID:10666593 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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