Figure 2
From: Intrinsically active MEK variants are differentially regulated by proteinases and phosphatases
In silico simulations predict easier closed to open transition in mutated MEKs. (A) Dynamic effects of mutations on MEK1 αA-helix. (structures) αA-helix most representative structures for unphosphorylated apo WT, Y130C and Q56P MEK1 simulations (in gray, blue and green respectively). For Y130C mutant two representative structures (corresponding to the WT-like and odd simulations) are depicted. (graphs) RMSD of the αA-helix with respect to that in 3EQD MEK1 X-ray crystal structure: WT, Y130C, and Q56P (same color code as above). Dotted lines indicate the RMSD average value among the three simulations. (B) Effects of mutations on P-loop flexibility. (structures) P-loop most representative structures for unphosphorylated apo WT, Y130C and Q56P MEK1 simulations (same color code as above). (graphs) Residue RMSD of the P-loop with respect to 3EQD MEK1 X-ray crystal structure: WT, Y130C and Q56P. Dotted lines indicate the RMSD average value among the three simulations. (C) Free-energy surface of wild-type MEK1 and the three mutants as a function of CV1 (x-axis) and CV2 (y-axis). A cross indicates the global free energy minimum for which a representative structure is shown below. Each minimum is also named according to the corresponding main feature. The contour lines are drawn every 10 kJ/mol. In the structures below, the αA-helix is show in light blue, the αC-helix in orange, the A-loop in magenta. The mutated residues are shown in red. (D) Comparison of WT A-loop closed conformation with Q56P mutant structures of the free energy minima corresponding to the fully open state showing a partial αC-helix rotation toward the catalytic site (αC-in): the αA-helix is show in light blue, the P-loop in green, the αC-helix in orange, A-loop in magenta. The mutated residues are in red. (E) Free-energy surface of wild-type MEK1 and the three mutants as a function of CV1 (x-axis) and CV3 (y-axis). Each minimum is named according to the corresponding main feature. The contour lines are drawn every 10 kJ/mol. In the structures below, the αA-helix is show in light blue, the P-loop in green, the αC-helix in orange, the A-loop in magenta. DFG-motif D208 and F209 residues are shown in yellow, and the mutated residues in red.
