1a92
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(New page: 200px<br /><applet load="1a92" size="450" color="white" frame="true" align="right" spinBox="true" caption="1a92, resolution 1.8Å" /> '''OLIGOMERIZATION DOMAI...)
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Revision as of 08:34, 20 November 2007
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OLIGOMERIZATION DOMAIN OF HEPATITIS DELTA ANTIGEN
Overview
BACKGROUND: The hepatitis D virus (HDV) is a small satellite virus of, hepatitis B virus (HBV). Coinfection with HBV and HDV causes severe liver, disease in humans. The small 195 amino-acid form of the hepatitis delta, antigen (HDAg) functions as a trans activator of HDV replication. A larger, form of the protein containing a 19 amino acid C-terminal extension, inhibits viral replication. Both of these functions are mediated in part, by a stretch of amino acids predicted to form a coiled coil (residues, 13-48) that is common to both forms. It is believed that HDAg forms dimers, and higher ordered structures through this coiled-coil region. RESULTS:, The high-resolution crystal structure of a synthetic peptide corresponding, to residues 12 to 60 of HDAg has been solved. The peptide forms an, antiparallel coiled coil, with hydrophobic residues near the termini of, each peptide forming an extensive hydrophobic core with residues, C-terminal to the coiled-coil domain in the dimer protein. The structure, shows how HDAg forms dimers, but also shows the dimers forming an octamer, that forms a 50 A ring lined with basic sidechains. This is confirmed by, cross-linking studies of full-length recombinant small HDAg. CONCLUSIONS:, HDAg dimerizes through an antiparallel coiled coil. Dimers then associate, further to form octamers through residues in the coiled-coil domain and, residues C-terminal to this region. Our findings suggest that the, structure of HDAg represents a previously unseen organization of a, nucleocapsid protein and raise the possibility that the N terminus may, play a role in binding the viral RNA.
About this Structure
1A92 is a Single protein structure of sequence from Hepatitis delta virus. Full crystallographic information is available from OCA.
Reference
Structural basis of the oligomerization of hepatitis delta antigen., Zuccola HJ, Rozzelle JE, Lemon SM, Erickson BW, Hogle JM, Structure. 1998 Jul 15;6(7):821-30. PMID:9687364
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