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. 2020 Oct 13;9:e60581. doi: 10.7554/eLife.60581

Figure 3. PfELC adopts an atypical fold.

(a) The N-lobe of scallop myosin 2 ELC (ScMyo2) is compared to (b) the N-lobe of PfELC. The two lobes are conserved in structure, and adopt a closed conformation. In contrast, the C-lobe of ScMyo2 ELC (c) and PfELC (d) differ. The most divergent feature is the much shorter α5* helix (comprised of only one turn) and the presence of the short α5’* helix in PfMyoA. (e) shows the elongated inter-lobe linker of ScELC (red) compared with (f) the kinked, hairpin-like inter-lobe linker of PfELC (light blue). The specific structure of the inter-lobe linker makes the PfELC structure more compact than canonical ELCs and no direct interaction can occur between the lobes in PfMyoA to encircle the heavy chain, contrary to what is seen in the case of ScMyo2.

Figure 3.

Figure 3—figure supplement 1. MTIP bound to PfMyoA.

Figure 3—figure supplement 1.

(a) Sequence alignment of PfMyoA IQ2 with conventional IQ motifs. Residues at consensus positions are colored in blue. (b) MTIP is bound to the heavy chain (HC) in a similar manner as a conventional ELC. Several residues from the consensus are conserved in PfIQ2. (c) Zoom on the specific contacts involved in the MTIP/PfMyoA recognition. (d, e) The recognition of the HC by MTIP is highly similar to the recognition of the HC by TgMLC1 (PDB 5VT9) and the residues involved in the apical salt bridge and the inter-lobe clamp (dotted lines) (Green et al., 2017) are conserved. (f) and (g) Interface between PfELC and MTIP. (f) The interface between PfELC and MTIP is hydrophobic and includes two aromatic residues (PfMTIPH150, PfMTIPW171) that maintain the relative positioning of the two light chains. A 132°angle occurs between the two HC helices that contain the PfIQ1 and PfIQ2 motifs. The kink is facilitated by the presence of a proline at the hinge (P802). (g) Alignment of the two molecules of the asymmetric unit in the PfMyoA•FL-PPS crystal structure. The hinge at the PfELC/MTIP interface is a restricted point of compliance since ~10° difference is found for the orientation of the PfIQ2 motif HC helices for these two molecules, when the structures are aligned using the PfIQ1 motif residues.