Franke C, Matschl U, Bruns M. Enzymatic treatment of duck hepatitis B virus: topology of the surface proteins for virions and noninfectious subviral particles.
Virology 2006;
359:126-36. [PMID:
17045625 DOI:
10.1016/j.virol.2006.09.006]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/14/2006] [Accepted: 09/02/2006] [Indexed: 12/29/2022]
Abstract
The large surface antigen L of duck hepatitis B virus exhibits a mixed topology with the preS domains of the protein alternatively exposed to the particles' interior or exterior. After separating virions from subviral particles (SVPs), we compared their L topologies and showed that both particle types exhibit the same amount of L with the following differences: 1--preS of intact virions was enzymatically digested with chymotrypsin, whereas in SVPs only half of preS was accessible, 2--phosphorylation of L at S118 was completely removed by phosphatase treatment only in virions, 3--iodine-125 labeling disclosed a higher ratio of exposed preS to S domains in virions compared to SVPs. These data point towards different surface architectures of virions and SVPs. Because the preS domain acts in binding to a cellular receptor of hepatocytes, our findings implicate the exclusion of SVPs as competitors for the receptor binding and entry of virions.
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