1ifd
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MODEL-BUILDING STUDIES OF INOVIRUS: GENETIC VARIATIONS ON A GEOMETRIC THEME
OverviewOverview
Inovirus (filamentous bacteriophage) is a simple system for studying the, rules by which protein primary structure (amino acid sequence) controls, secondary and higher order structure, and thereby function. The virus, occurs naturally as a number of different strains with similar secondary, and higher order structure, but the protein subunit that assembles to form, the virion coat has quite different primary structures in different virus, strains. Despite these differences in primary structure, the subunits of, all strains have much the same size, about 50 residues, which are, distributed by type in much the same way into three domains of primary, structure: a collection of acidic residues in the N-terminal region, a, hydrophobic domain of about 19 residues near the middle, and a collection, of basic residues near the C-terminus. Each subunit can be closely, approximated by an alpha-helix with its long axis roughly parallel to the, fibre axis, sloping from large to small radius in the virion and, interleaving between subunits in the next turn or level. The acidic, residues near the N-terminus of the subunit face outwards on the virion, surface, and explain the low isoelectric point of the virion; the basic, residues near the C-terminus face inwards, where they neutralize the, charge on the DNA at the core of the virion; and the hydrophobic central, domain is involved in interactions which bind neighbouring subunits., Detailed X-ray fibre diffraction analysis of one strain gives the subunit, structure. Comparative model-building studies of different strains, illustrate the common structural principles.
About this StructureAbout this Structure
1IFD is a Single protein structure of sequence from Phage phi3t. Full crystallographic information is available from OCA.
ReferenceReference
Model-building studies of Inovirus: genetic variations on a geometric theme., Marvin DA, Int J Biol Macromol. 1990 Apr;12(2):125-38. PMID:2078529
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