Fig. 3: Negative constraints on purple Dprs 11/15/16/17 which prevent binding to the blue DIP-α.
From: DIP/Dpr interactions and the evolutionary design of specificity in protein families
a Alignment of interfacial residues of the four purple group Dprs and of Dpr10. Residues are color-coded based on the calculated ΔΔG, as specified in the color bar at the top of the figure. Predicted negative constraint positions are in gray. The average KD and the experimental error for wild-type DIP-α/Dpr10 interaction based on six independent experiments is given on the left of the alignment. All calculations are carried out on the DIP-α/Dpr10 complex indicated to the left of the figure. The arrows indicate that residues in Dpr10 were computationally mutated to those of the four purple Dprs, as indicated. b Structural details of wild-type environment for each position where a mutation is predicted to cause a negative constraint (enclosed in a bold box). c, d SPR binding analysis of Dpr10 and Dpr11 mutants, representing negative constraints, to DIP-α. Each row shows SPR sensorgrams of Dpr analytes binding over a DIP-α immobilized surface. An overlay of the binding isotherms for each surface is shown to the right. KD (ΔΔG) values for each DIP/Dpr interaction are listed below the SPR sensorgrams. For each KD, the number in parenthesis represents the fitting error in the last significant figure, in μM for a single experiment with an expected experimental error up to 15%. Family-wide numbering of interfacial positions is used for all the mutants. Uniprot numbering is given in curly brackets. Source data are provided as a Source Data file.
