Figure 2. Class 2 docking domain structures.

(A) GH dock. In the upper stereo diagram, monomers are shown with different shades of orange (^ACPdd) or cyan (dd^KS). The GlySer linker (green) connects the upstream ^ACPdd C-terminus and the downstream dd^KS N-terminus. Connections to the ACP and KS domains are shown with thick lines. Close-up stereoviews are shown of the Class 2-specific ^ACPdd_G α1 interface with ${\text{dd}}_{\mathrm{H}}^{\text{KS}}$ αA and αB (purple box) and the common ^ACPdd_G α2 interface with ${\text{dd}}_{\mathrm{H}}^{\text{KS}}$ α B coiled-coil (red box). Hydrophobic contacts in the docking interface are shown as sticks with orange C for the ^ACPdd, cyan C for the dd^KS, red O and blue N.

(B) KL dock. Coloring and labeling are as in A. Zoomed-in stereoviews of the boxed regions of the upper stereo diagram are highlighted below. Electrostatic interactions that may promote selectivity are labeled, and hydrogen bonds are indicated with red dashes (detail in Figure S2E, F). See also Figure S2.