title: A novel complex formed between the flavivirus E and NS1 proteins: analysis of its structure and function.
abstract: We examined the structural features and functional significance of a novel complex which forms between the envelope (E) protein and nonstructural protein NS1 of Murray Valley encephalitis (MVE) virus. Western blot analysis of virus-infected C6/36 cell lysates revealed that the undenatured form of this E-NS1 complex was a heat-sensitive E-(NS1 dimer) complex. Furthermore, the E-NS1 complex was observed in cells infected with Kunjin, Japanese encephalitis, West-Nile and Kokobera viruses which indicates the complex is a common feature of flavivirus infection. E-NS1 complex which had been immunoaffinity purified from MVE-infected cell lysates or eluted from gel slices exhibited partial breakdown into the individual monomers, demonstrating that the complex arose from the association of E and NS1 proteins and was not a single polypeptide created from incomplete gene cleavage. Radioimmunoprecipitation and western blot analysis of MVE-infected cell lysates and culture fluid preparations collected at various times after infection revealed that the E-NS1 complex has a long half life, accumulates in the virus-infected cell with time and is not secreted into the extracellular fluid. We have postulated that the E-NS1 complex, or at least a major portion of the complex, is a non-specific aggregation with no functional significance in the viral life cycle.
authors.affiliation: Department of Microbiology, University of Western Australia, QE II Medical Centre, Nedlands.
authors.forename: B J
authors.initials: BJ
authors.lastname: Blitvich
authors.forename: J S
authors.initials: JS
authors.lastname: Mackenzie
authors.forename: R J
authors.initials: RJ
authors.lastname: Coelen
authors.forename: M J
authors.initials: MJ
authors.lastname: Howard
authors.forename: R A
authors.initials: RA
authors.lastname: Hall
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D002846:Chromatography, Affinity / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D018068:Encephalitis Virus, Murray Valley / Q000502:physiology*; D011485:Protein Binding; D013329:Structure-Activity Relationship; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000302:isolation & purification / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins; C065696:glycoprotein E, Flavivirus