This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cornillez-Ty, C. T. Articles by Lazinski, D. W. Search for Related Content PubMed PubMed Citation Articles by Cornillez-Ty, C. T. Articles by Lazinski, D. W.

 Previous Article  |  Next Article 

Journal of Virology, October 2003, p. 10314-10326, Vol. 77, No. 19
0022-538X/03/$08.00+0     DOI: 10.1128/JVI.77.19.10314-10326.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Determination of the Multimerization State of the Hepatitis Delta Virus Antigens In Vivo

Department of Molecular Biology and Microbiology and the Raymond and Beverly Sackler Research Foundation Laboratory, Tufts University School of Medicine, Boston, Massachusetts 02111

Received 23 April 2003/ Accepted 11 July 2003

Hepatitis delta virus expresses two essential proteins, the small and large delta antigens, and both are required for viral propagation. Proper function of each protein depends on the presence of a common amino-terminal multimerization domain. A crystal structure, solved using a peptide fragment that contained residues 12 to 60, depicts the formation of an octameric ring composed of antiparallel coiled-coil dimers. Because this crystal structure was solved for only a fragment of the delta antigens, it is unknown whether octamers actually form in vivo at physiological protein concentrations and in the context of either intact delta antigen. To test the relevance of the octameric structure, we developed a new method to probe coiled-coil structures in vivo. We generated a panel of mutants containing cysteine substitutions at strategic locations within the predicted monomer-monomer interface and the dimer-dimer interface. Since the small delta antigen contains no cysteine residues, treatment of cell extracts with a mild oxidizing reagent was expected to induce disulfide bond formation only when the appropriate pairs of cysteine substitution mutants were coexpressed. We indeed found that, in vivo, both the small and large delta antigens assembled as antiparallel coiled-coil dimers. Likewise, we found that both proteins could assume an octameric quaternary structure in vivo. Finally, during the course of these experiments, we found that unprenylated large delta antigen molecules could be disulfide cross-linked via the sole cysteine residue located within the carboxy terminus. Therefore, in vivo, the C terminus likely provides an additional site of protein-protein interaction for the large delta antigen.

This article has been cited by other articles:

• Nellissery, J. K., Szczepaniak, R., Lamberti, C., Weller, S. K. (2007). A Putative Leucine Zipper within the Herpes Simplex Virus Type 1 UL6 Protein Is Required for Portal Ring Formation. J. Virol. 81: 8868-8877 [Abstract] [Full Text]  
• O'Malley, B., Lazinski, D. W. (2005). Roles of Carboxyl-Terminal and Farnesylated Residues in the Functions of the Large Hepatitis Delta Antigen. J. Virol. 79: 1142-1153 [Abstract] [Full Text]