Fig. 3: Recognition of coagulation factor FIX.
From: Structural insight into bicarbonate-mediated carboxylation by human vitamin K-dependent carboxylase
a Overall view of the interaction between GGCX and FIX. FIX is shown as an orange cartoon, while GGCX is displayed in surface representation and colored according to its structural domains. b Overall view of the propeptide binding to GGCX. GGCX clamp A and clamp B are displayed in electrostatic surface representation, with negative charges in red and positive charges in blue. The propeptide is shown in cartoon representation, with its three key interaction regions marked by dashed boxes in blue, green, and cyan. c Close-up view of glutamate (Glu) substrate recognition by GGCX, showing the key interactions that enable specificity for the substrate. d Multiple sequence alignment of the GLA domain across human VKD proteins. Carboxylation sites are marked in red, and upstream residues (denoted as “Eup”) are highlighted with colored boxes according to their chemical properties. The frequency of each amino acid type at “Eup” positions is summarized below the alignment. e Recognition of the dipeptide Gla7-Glu8 in the GGCX-FIXGlaE complex. Residues involved in dipeptide binding are shown in detail.
