HCMV gB ectodomain structure.

<p>(A) Schematic representation of the full-length HCMV gB (top) and the crystallized construct, gB78-706-7M-E (bottom). Disulfide bonds are represented as black brackets, antigenic domains (AD-1-5) are indicated in blue brackets, and mutations are shown using red bars. Structural domains, are colored as follows: domain I = blue, II = green, III = yellow, IV = orange, V = red, as in [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005227#ppat.1005227.ref016" target="_blank">16</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005227#ppat.1005227.ref017" target="_blank">17</a>]. SS = signal sequence, MPR = membrane proximal region, TM = transmembrane domain, and Cyto = cytoplasmic domain. Numbers denote construct boundaries. (B) The crystal structure of the HCMV gB ectodomain is shown as a protomer and a trimer in cartoon representation as well as a trimer in surface representation. Chain B is colored by domain as in (A). (C) Side and top down view of the coiled coil in DIII with a coordinated calcium ion (CA) (blue sphere). Side chains of D508 (yellow) with carboxyl oxygens (red) and C506 (green) are also shown. Dashed lines indicate distances between the carboxyl oxygens in D508 and the calcium ion. All structure figures were made in Pymol (<a href="http://www.pymol.org" target="_blank">http://www.pymol.org</a>).