title: The herpes simplex virus triplex protein, VP23, exists as a molten globule.
abstract: Two proteins, VP19C (50,260 Da) and VP23 (34,268 Da), make up the triplexes which connect adjacent hexons and pentons in the herpes simplex virus type 1 capsid. VP23 was expressed in Escherichia coli and purified to homogeneity by Ni-agarose affinity chromatography. In vitro capsid assembly experiments demonstrated that the purified protein was functionally active. Its physical status was examined by differential scanning calorimetry, ultracentrifugation, size exclusion chromatography, circular dichroism, fluorescence spectroscopy, and 8-anilino-1-naphthalene sulfonate binding studies. These studies established that the bacterially expressed VP23 exhibits properties consistent with its being in a partially folded, molten globule state. We propose that the molten globule represents a functionally relevant intermediate which is necessary to allow VP23 to undergo interaction with VP19C in the process of capsid assembly.
authors.affiliation: Edinburgh Centre for Protein Technology, Department of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom.
authors.forename: M D
authors.initials: MD
authors.lastname: Kirkitadze
authors.forename: P N
authors.initials: PN
authors.lastname: Barlow
authors.forename: N C
authors.initials: NC
authors.lastname: Price
authors.forename: S M
authors.initials: SM
authors.lastname: Kelly
authors.forename: C J
authors.initials: CJ
authors.lastname: Boutell
authors.forename: F J
authors.initials: FJ
authors.lastname: Rixon
authors.forename: D A
authors.initials: DA
authors.lastname: McClelland
mesh_terms: D001483:Base Sequence; D002213:Capsid / Q000737:chemistry* / Q000235:genetics; D036022:Capsid Proteins; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D018259:Herpesvirus 1, Human / Q000737:chemistry* / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D036022:Capsid Proteins; D017931:DNA Primers; D011993:Recombinant Fusion Proteins; C082563:VP19 protein, Human herpesvirus 1; C079750:VP23 protein, Human herpesvirus 1