Fig. 4: Allosteric regulation of GGCX.
From: Structural insight into bicarbonate-mediated carboxylation by human vitamin K-dependent carboxylase
a Structural comparison between the GGCX apo state and GGCX-FIX complex in two orthographic views. The apo state of GGCX is displayed in gray, while GGCX-FIX complex is color-coded as in Fig. 1d. Both structures are shown in cartoon representation, with regions that undergo dramatic changes are denoted with red arrows. The wedge angle between the two clamps transits from ~65° to ~45°. b Structural comparison of the two clamps in GGCX apo state (upper) and GGCX-FIX complex (bottom). The FIX (orange cartoon) is superimposed to the apo state of GGCX. The two clamps are shown as surface representation. c Structural comparison of the clamp regions and VK-binding cap domain connections between the GGCX apo state (left) and the GGCX-FIX complex (right). Key interacting regions are highlighted to illustrate structural shifts upon FIX binding. d Structural comparison of the VK-binding cap domain between GGCX apo state (left) and GGCX-FIX complex (right). Vitamin K is superimposed to the apo state and depicted as sticks. e Close-up view of the LL9 loop in the GGCX apo state and the GGCX-FIX complex. The apo state is shown in gray, while the GGCX-FIX complex is color-coded as in Fig. 1d. The comparison highlights structural clashes (magenta box marks) in the apo state with the M402GGCX-apo occupying the position of Leu6FIX.
