Structures of the ABPBG10 subunit (panels A1–2) and of the ABPBG2 subunit (panels B1–4) threaded on model c2ejnB with sites of interest indicated.

<p>Panels A1, A2, B1, and B2 are in cartoon format with alpha helices represented by helical ribbons and loops as thinner connecting lines. Panels B3 and B4 are space-filling models with amino acid residues as filled spheres. The conserved residues involved in ligand binding and subunit coordination in the dimer <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115454#pone.0115454-Karn7" target="_blank">[43]</a> are colored tan and ½-Cys residues are colored yellow. Panel A1 shows the exterior face of the ABPBG10 subunit and panel A2 shows its interior face (the N-terminal residue is in green dotted spheres and the C-terminal residue is in red dotted spheres). Panels B1–4 show residues under selection in the tear ABPBGs. Panels B1 and B3 are exterior views and panels B2 and B4 are interior views. Residues in red are selected with a BEB posterior probability of 99%; those in green with BEB posterior probabilities of 95%; and those in blue with a BEB posterior probability of 90% (the N-terminal ½-Cys residue is a yellow dotted sphere; the C-terminal residue is magenta).