title: Interdomain interactions within the gene 3 protein of filamentous phage.
abstract: Infection of Escherichia coli by filamentous phage fd is mediated by the phage gene 3 protein (g3p). The g3p consists of three domains (g3p-D1, D2 and D3) linked by flexible glycine-rich linkers. All three domains are indispensable for phage infectivity; the g3p-D1 domain binds to the TolA receptor presumably at the inner face of the outer membrane, the g3p-D2 domain to the F-pilus and the g3p-D3 domain anchors g3p to the phage coat. The N-terminal domains g3p-D1 and D2 interact with each other; this interaction is abrogated by binding of g3p-D2 to the F-pilus leading to the release of g3p-D1 to bind to TolA. Here, using phages with deletions in g3p, we have discovered a specific interaction between the two N-terminal domains and g3p-D3, the C-terminal domain of g3p. We propose that these interdomain interactions within g3p lead to a compact and stable organisation when displayed on the phage tip, but that during infection, this compact state must be unraveled.
authors.affiliation: Centre for Protein Engineering, MRC Centre, Hills Road, Cambridge, UK.
authors.forename: J
authors.initials: J
authors.lastname: Chatellier
authors.forename: O
authors.initials: O
authors.lastname: Hartley
authors.forename: A D
authors.initials: AD
authors.lastname: Griffiths
authors.forename: A R
authors.initials: AR
authors.lastname: Fersht
authors.forename: G
authors.initials: G
authors.lastname: Winter
authors.forename: L
authors.initials: L
authors.lastname: Riechmann
mesh_terms: D036022:Capsid Proteins; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004926:Escherichia coli / Q000821:virology; D017912:Inovirus / Q000737:chemistry* / Q000472:pathogenicity; D014760:Viral Fusion Proteins / Q000737:chemistry*
chemical_list: D036022:Capsid Proteins; D004268:DNA-Binding Proteins; D014760:Viral Fusion Proteins