The Cysteine-Rich Interdomain Region from the Highly Variable Plasmodium falciparum Erythrocyte Membrane Protein-1 Exhibits a Conserved Structure
Figure 6
The three-helix bundles of MC179 and the DBL domains.
All four structures were aligned using the alpha carbon atoms of the H1 and H2 helices, then were translated apart for viewing. In subdomain 3, the similarity of the H1 (dark blue) and H2 (light blue) helices is apparent, but the H3 (red) helices differ among molecules. MC179 and the EBA-175 F1 DBL each contain regular H3 helices, but the F2 and Pkα DBL domains have irregular H3 helices. Nevertheless, these degenerate helices meander to a pair of conserved cysteines that make conserved bonds to H1 and H2, as in MC179 and in the F1 domain. DBL domains contain another three-helix bundle (h1, h2, h3) in the N-terminal half (subdomain 2) of the molecule that is colored here analogously to the MC179 H1, H2, H3, and connecting helices. Several characteristics of these N-terminal bundles suggest their relatedness to the MC179 bundle and to the C-terminal DBL bundles (see text). N- and C-termini (N, C) are labeled.