Fig. 5.

Isolation of DARPin variants with altered ERK2 specificity. a Survival curves for serially diluted E. coli MC4100 cells co-expressing TatABC along with ERK2-Bla and Tat-targeted DARPins EpEM6 (dark gray diamonds) and EpEM7 (black diamonds). Resistance of cells was evaluated in the presence (left) or absence (right) of MEK1^R4F kinase as indicated. Overnight cultures were serially diluted in liquid LB and plated on LB agar supplemented with Carb. Maximal cell dilution that allowed growth is plotted versus Carb concentration. Resistance profiles for pERK2-specific DARPins pE59 (empty circles) and pEM1 (empty diamonds) are shown with (left) and without (right) MEK1^R4F for comparison. b Location of mutations in DARPin variants EpEM6 and EpEM7 mapped onto the pE59-pERK2 co-crystal structure. The structure was derived from PDB ID 3ZUV described in Kummer et al.³⁰, and the schematic was generated using PyMOL software. The DARPin is shown in light red, and the mutations found in helix and loop secondary structures in red and green, respectively. Source data for this figure is available in the Source Data File