Figure 7

CLK β 7- β 8 hairpin insert and anchoring residues. Comparison of the residue interactions anchoring the β-hairpin insert to the kinase C-lobe in solved structures of PfLAMMER [PDB:3LLT] and human Clk2 [PDB:3NR9]. (A) Both structures superimposed, with corresponding key residues shown in "sticks" representation. The contrastingly conserved residue (from CHAIN analysis) is highlighted cyan: D653 in PfLAMMER, Q266 in human Clk2. A residue of interest near the base of the hairpin insert, discussed in the text, is shown in yellow; its type is not strongly conserved within apicomplexan CLKs. Two residues in the loop of the hairpin, colored green, are inserts in PfLAMMER relative to Clk2; they appear anchored to the kinase C-lobe by interactions with a lysine, dark blue. (B) Human Clk2, showing side chains near the residues of interest. A hydrogen bond appears between the αE-helix glutamine (cyan) and the backbone of a valine (yellow) near the base of the hairpin insert. (C) In PfLAMMER, the two residues of interest, D653 (cyan) and T711 (yellow), do not interact directly; each instead forms several novel hydrogen bonds with other nearby residues, shown in green and blue, corresponding to those shown in green and gray in the human Clk2 structure.