10.1371/journal.pone.0041912.g004 Figure 4  Crystal packing generates a RON homodimer interface that overlaps with the putative MSPβ binding site predicted based on the Met/HGF structure.
(A) Left panel: Surface and ribbon representations of symmetry-related RON Sema-PSI molecules. Right panel: Close-up view of the interface and the molecules rotated by ∼90°. (B) Surface and ribbon representation of the modeled RON Sema-PSI/MSPβ complex derived based on the free MSPβ (PDB code 2ASU) and RON Sema-PSI structures superposed onto the structure of Met Sema-PSI/HGFβ (PDB entry 1SHY). The molecular surfaces of RON Sema-PSI (blue) and MSPβ (pink) are shown in transparent colors and secondary structural elements are shown in ribbon representation. (C) Stereoscopic representations of the RON Sema homodimer interface residues generated by crystal packing. The two subunits are colored gray and sky blue. Selected amino acids are colored in the atomic color scheme: red, oxygen; blue, nitrogen; dark yellow, sulfur; bright yellow, acetate carbon.