1ql2: Difference between revisions
New page: left|200px<br /><applet load="1ql2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ql2, resolution 3.1Å" /> '''INOVIRUS (FILAMENTOUS... |
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[[Image:1ql2.gif|left|200px]]<br /><applet load="1ql2" size=" | [[Image:1ql2.gif|left|200px]]<br /><applet load="1ql2" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ql2, resolution 3.1Å" /> | caption="1ql2, resolution 3.1Å" /> | ||
'''INOVIRUS (FILAMENTOUS BACTERIOPHAGE) STRAIN PF1 MAJOR COAT PROTEIN ASSEMBLY'''<br /> | '''INOVIRUS (FILAMENTOUS BACTERIOPHAGE) STRAIN PF1 MAJOR COAT PROTEIN ASSEMBLY'''<br /> | ||
==Overview== | ==Overview== | ||
The major coat protein in the capsid of Pf1 filamentous bacteriophage | 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. | ||
==About this Structure== | ==About this Structure== | ||
1QL2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_phage_pf1 Pseudomonas phage pf1]. Full crystallographic information is available from [http:// | 1QL2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_phage_pf1 Pseudomonas phage pf1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QL2 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Pseudomonas phage pf1]] | [[Category: Pseudomonas phage pf1]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Marvin, D | [[Category: Marvin, D A.]] | ||
[[Category: Symmons, M | [[Category: Symmons, M F.]] | ||
[[Category: Welsh, L | [[Category: Welsh, L C.]] | ||
[[Category: helical virus]] | [[Category: helical virus]] | ||
[[Category: helical virus coat protein]] | [[Category: helical virus coat protein]] | ||
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[[Category: ssdna viruses]] | [[Category: ssdna viruses]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:40:50 2008'' | ||
Revision as of 15:40, 21 February 2008
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INOVIRUS (FILAMENTOUS BACTERIOPHAGE) STRAIN PF1 MAJOR COAT PROTEIN ASSEMBLY
OverviewOverview
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.
About this StructureAbout this Structure
1QL2 is a Single protein structure of sequence from Pseudomonas phage pf1. Full crystallographic information is available from OCA.
ReferenceReference
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
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