Journal of General Virology

Mutational analysis of the major heparan sulfate-binding domain of herpes simplex virus type 1 glycoprotein C

Kristina Mårdberg,¹ Edward Trybala,¹ Joseph C. Glorioso² and Tomas Bergström¹

¹ Department of Virology, Göteborg University, Guldhedsgatan 10b, S-413 46 Göteborg, Sweden
² Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA

Heparan sulfate (HS) has been identified as a receptor molecule for numerous microbial pathogens, including herpes simplex virus type 1 (HSV-1). To further define the major HS-binding domain of the HSV-1 attachment protein, i.e. glycoprotein C (gC), virus mutants carrying alterations of either two neighbouring basic amino acid residues or a single hydrophobic amino acid residue within the N-terminal domain of the protein (residues 26–227) were constructed. In addition, a mutant lacking the Asn148 glycosylation site was included in the study. Binding of purified mutated gC proteins to isolated HS chains showed that viruses with mutations at residues Arg(129,130), Ile142, Arg(143,145), Arg(145,147), Arg(151,155) and Arg(155,160) had significantly impaired HS binding, in contrast to the other mutations, including Asn148. Impairment of the HS-binding activity of gC by these mutations had profound consequences for virus attachment and infection of cells in which amounts of HS exposed on the cell surface had been reduced. It is suggested that basic and hydrophobic residues localized at the Cys127–Cys144 loop of HSV-1 gC constitute a major HS-binding domain, with the most active amino acids situated near the C-terminal region of the two cysteines.

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© 2001 SGM

This article is now available in the August 2001 print issue of JGV (vol. 82, 1941–1950). The complete issue of the journal may be seen in electronic form on JGV Online.