Figure 2.
Fig. 2. Structure of Fus3-Ste5 complex and comparison to
canonical docking complexes. (A) Crystal structure of
Fus3/Ste5_pep complex. Ste5 (red) binds to Fus3 in a bipartite
manner. Close-up views of site A and site B on the right are
shown with simulated annealed electron density omit maps
(contoured at 1 ) for the Ste5
peptide. (B) Structure of Fus3 in complex with a canonical
docking motif from Ste7 (Ste7_pep1) (16). (C) Protein-protein
interactions at site A. The N-terminal half of Ste5_pep adopts a
ß-strand conformation and initiates the formation of a new
ß strand at the N terminus of Fus3 (ß0). This strand
forms eight backbone-backbone H bonds with the Fus3 N-terminal
region (H bonds are indicated with red dashed lines). The side
chain of Q^292 is H bonded to the backbone of ß1, the
hydrophobic side chain of I^294 interacts with a groove on the
top of the kinase, and Y^295 makes an H bond with the side chain
of R^4 from Fus3. Schematic illustration of secondary structural
elements of the N-terminal kinase lobe in the unliganded and
Ste5_pep liganded complex is shown on the right. (D) Comparison
of protein-protein interactions at the canonical MAPK docking
groove (site B) between the Fus3/Ste5_pep and the Fus3/Far1_pep
complexes (16).
) for the Ste5
peptide. (B) Structure of Fus3 in complex with a canonical
docking motif from Ste7 (Ste7_pep1) (16). (C) Protein-protein
interactions at site A. The N-terminal half of Ste5_pep adopts a
ß-strand conformation and initiates the formation of a new
ß strand at the N terminus of Fus3 (ß0). This strand
forms eight backbone-backbone H bonds with the Fus3 N-terminal
region (H bonds are indicated with red dashed lines). The side
chain of Q^292 is H bonded to the backbone of ß1, the
hydrophobic side chain of I^294 interacts with a groove on the
top of the kinase, and Y^295 makes an H bond with the side chain
of R^4 from Fus3. Schematic illustration of secondary structural
elements of the N-terminal kinase lobe in the unliganded and
Ste5_pep liganded complex is shown on the right. (D) Comparison
of protein-protein interactions at the canonical MAPK docking
groove (site B) between the Fus3/Ste5_pep and the Fus3/Far1_pep
complexes (16).