1.G.5 The Viral Pore-forming Membrane Fusion Protein-5 (VMFP5) Family

The Vesicular Stomatitis Virus (VSV) G protein and the HSV-1gB fusion protein are of Class III. They do not require proteolytic processing for function and consist of both α- and β-structure. The native trimers remain trimers upon membrane insertion to promote pore formation and fusion (White et al. 2008).  The fusogenic transition entails an extensive structural reorganization of G (Roche et al., 2007).  In the prefusion form, G has the shape of a tripod with the fusion loops exposed, which point toward the viral membrane with the antigenic sites located at the distal end of the molecule. A large number of G glycoproteins, perhaps organized as in the crystals, act cooperatively to induce membrane merging. Fusion occurs in the endosome in response to the acidic pH.  The transmembrane domain in the G protein may induce positive intrinsic curvature and thereby induce formation of fusion pores (Sengupta et al. 2014).



Roche, S., F.A. Rey, Y. Gaudin, and S. Bressanelli. (2007). Structure of the prefusion form of the vesicular stomatitis virus glycoprotein G. Science 315: 843-848.

Sengupta, T., H. Chakraborty, and B.R. Lentz. (2014). The Transmembrane Domain Peptide of Vesicular Stomatitis Virus Promotes Both Intermediate and Pore Formation during PEG-Mediated Vesicle Fusion. Biophys. J. 107: 1318-1326.

White, J.M., S.E. Delos, M. Brecher, and K. Schornberg. (2008). Structures and mechanisms of viral membrane fusion proteins: multiple variations on a common theme. Crit. Rev. Biochem. Mol. Biol. 43: 189-219.


TC#NameOrganismal TypeExample
1.G.5.1.1The Vesicular Stomatitis Virus (VSV) Glycoprotein G (423 aas) VirusGlycoprotein G of Vesicular Stomatitis Virus (P0C2X0)

Glycoprotein G of 508 aas.

G of Monopterus albus rhabdovirus


Virion transmembrane glycoprotein of 662 aas

VTG of Obodhiang virus


Glycoprotein G of 524 aas.

G of Rabies virus