Schematic of CR1.

<p>(<b>A</b>) Main cartoon shows the 30 CCPs (ovals) in the ectodomain of the most common CR1 size-variant. Long-homologous repeats (LHRs) and positions of functional sites (dark grey) are indicated; the eight-residue linker between long-homologous repeats C and D is drawn as a dotted line along with neighbouring modules (grey); CCPs 24/25 wherein reside the <i>Sl1/2</i> and <i>McC^a/b</i>-encoded antigens are also highlighted (thicker outline) and their modeled 3D structures <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034820#pone.0034820-Soares1" target="_blank">[43]</a> drawn as cartoons with K1590 and R1601 side chains shown as spheres.