Similar linear arrangement of putative domain structures of BDV G, VSV G, THOV GP and AcMNPV GP64 and herpesvirus gB. Class III VFP domain nomenclature and coloring is as in Fig. 1. Amino acids are numbered beginning after the putative signal sequences in VSV G, but at the beginning of the signal sequence of HSV-1 gB. Arrows indicate G and gB truncations of the forms used for crystallography. Solid lines represent cysteine bonding in VSV G, AcMNPV GP64, and HSV-1 and EBV gB [30, 32, 34, 43]. Black boxes represent hydrophobic regions, with violet representing the transmembrane anchor (TM). Dashed lines represent potential cysteine bonding in BDV G, THOV GP and CMV gB. Dashed arrow is the location of a furin cleavage site in the alphaherpesvirus varicella zoster virus (human herpes virus 3). Solid arrows are furin cleavage sites in BDV G, CMV gB, and EBV gB.