Figure 1: Overall structure of the gD/nectin-1 complex.

(a) A ribbon representation of the gD/nectin-1 complex structure. HSV-1 gD is coloured green and labelled according to Carfi et al.¹⁶. The N- and C-terminal extensions within gD, which contains nectin-1 binding site, are highlighted in blue and gold, respectively. The three-domained nectin-1 was labelled as in a recent report by Narita et al.²¹ The first V-set Ig domain (first Ig) of nectin-1 is coloured cyan. The second (second Ig) and the third (third Ig) domains, both exhibiting a C-set Ig fold, are coloured orange and magenta, respectively. Clearly, only the first Ig V-set domain of nectin-1 binds gD. (b,c) A magnified view of the gD molecule and the nectin-1 first Ig domain within the complex structure. The V-set Ig core of gD and the first Ig domain of nectin-1 are also shown in a surface representation in (b) to highlight the N- and C-terminal extensions in gD (including the nectin-1 contact residues). The residues bordering these terminal extensions (P23, I55, A185 and A253) are indicated and labelled. The interactive surface in Ig-like V-set domain of nectin-1 is coloured yellow in (b). The dash-line boxed part in (a) is clockwise rotated for about 30° or horizontally flipped for about 180° to yield (b) and (c), respectively.