Crystal Structure of Glycoprotein B from Herpes Simplex Virus 1

TLDR

Glycoprotein B is the most conserved component of herpes virus cell‑entry machinery, and fusion by class I and II proteins involves large‑scale conformational changes triggered by receptor binding. The crystal structure of HSV‑1 gB ectodomain shows a trimeric multidomain architecture with a coiled‑coil core and beta‑hairpin fusion peptides that align it with both class I and class II viral fusion proteins, suggesting a domain arrangement capable of the large‑scale rearrangements required for membrane fusion.

Abstract

Glycoprotein B (gB) is the most conserved component of the complex cell-entry machinery of herpes viruses. A crystal structure of the gB ectodomain from herpes simplex virus type 1 reveals a multidomain trimer with unexpected homology to glycoprotein G from vesicular stomatitis virus (VSV G). An alpha-helical coiled-coil core relates gB to class I viral membrane fusion glycoproteins; two extended beta hairpins with hydrophobic tips, homologous to fusion peptides in VSV G, relate gB to class II fusion proteins. Members of both classes accomplish fusion through a large-scale conformational change, triggered by a signal from a receptor-binding component. The domain connectivity within a gB monomer would permit such a rearrangement, including long-range translocations linked to viral and cellular membranes.