Fig. 6: The C-terminal hydrophobic patch of the bMERB domain is crucial for Rab8a interaction.
From: The mechanism of activation of the actin binding protein EHBP1 by Rab8 family members
a Cartoon depiction of the EHBP1 bMERBM1116A:Rab8aGppNHp complex. Rab8aGppNHp (gray, chain B) binds to EHBP1 bMERB (blue, chain D) via its N-terminal regions, the switch regions as well as the inter-switch region. Switch I and switch II are shown in red and blue, respectively. GppNHp and Mg2+ are depicted as sticks and a green sphere, respectively. b Schematic illustration of the interactions between the bMERB domain and Rab8aGppNHp. Hydrogen bonds and ionic interactions are shown in gray dashed lines and light orange dashed lines indicate hydrophobic interactions. RabSF1, RabF1, RabF2, RabF3, and RabF4 motifs are shown in orange, green, pink, purple, and brown respectively. c Electrostatic potential of the bMERB domain calculated in PyMOL using the APBS-PDB2PQR plugin and visualized in red to blue (−5 kT/e to +5 kT/e). The dashed line highlights the region that interacts with Rab8a. d The C-terminal hydrophobic patch of the EHBP1 bMERB domain. e–n Mutational characterization of the bMERB:Rab8a complex interface. Binding of GppNHp Rab8a1-176 with different EHBP1 bMERB mutants was systematically tested and affinities were measured by ITC experiments. The data are representative of at least three repetitions. N.D. denotes not detected.
