Project B01.2

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are highly prevalent human pathogens that cause lifelong infections with significant public health impact. Both viruses are large, double-stranded DNA viruses comprising an icosahedral capsid, surrounded by a proteinaceous tegument, and a lipid envelope containing viral glycoproteins [1]. HSV membrane glycoproteins form a coordinated network essential for viral entry, fusion, immune evasion, assembly and cell-to-cell spread [2]. HSV-1 and HSV-2 encode 12 envelope glycoproteins. Four core glycoproteins, gB, gD, gH, and gL, are required for membrane fusion and viral infectivity, whereas the remaining 8 glycoproteins (gC, gE/gI, gG, gJ, gK, and, gM/gN) play supporting or modulatory roles [3]. Research to date has primarily focused on gB, a highly conserved class III fusion protein that mediates fusion between the viral envelope and the host cell membrane. gB function is tightly regulated and depends on gD and gH/gL. Together, these four constitute the minimal fusion machinery [4]. Although structures of gB, gD, and gH/gL from distinct members of the Herpesviridae family have been determined using X-ray crystallography or electron cryo-microscopy (see rcsb.org), often as ectodomains rather than full-length proteins, many of the HSV-1 and HSV-2 envelope glycoproteins remain structurally unresolved.

The objective of this project is to determine high-resolution structures of previously uncharacterized full-length HSV-1 and HSV-2 glycoproteins using electron cryo-microscopy (cryo-EM) single particle analysis of purified overexpressed proteins.