title: Enzymatic treatment of duck hepatitis B virus: topology of the surface proteins for virions and noninfectious subviral particles.
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.
authors.affiliation: Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Martinistrasse 52, D-20251 Hamburg, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Franke
authors.forename: Urte
authors.initials: U
authors.lastname: Matschl
authors.forename: Michael
authors.initials: M
authors.lastname: Bruns
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002918:Chymotrypsin / Q000378:metabolism; D004372:Ducks; D004591:Electrophoresis, Polyacrylamide Gel; D015611:Hepatitis B Virus, Duck / Q000737:chemistry* / Q000302:isolation & purification; D007456:Iodine Isotopes; D008954:Models, Biological; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D044967:Serum / Q000821:virology; D013194:Staining and Labeling; D014461:Ultracentrifugation; D014759:Viral Envelope Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014771:Virion / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D007456:Iodine Isotopes; C077433:Pre-S protein, Duck hepatitis B virus; D014759:Viral Envelope Proteins; D010744:Phosphoric Monoester Hydrolases; D002918:Chymotrypsin