FIGURE 5.

Structure of the C-terminal portion of ACAP1. A, the structure of the C-terminal portion of ACAP1 shown at two different orientations. The GAP domain is colored blue. The ANK domain is colored red. The zinc ion is shown as a gray sphere. The secondary structural elements (α-helices and β-sheets) are also labeled. B, comparing the GAP domain of ACAP1 with the corresponding domains in ASAP2 and ASAP3. The three structures are shown in schematic representation and superimposed based on their ANK domains. ACAP1 is colored blue, ASAP2 is colored green, and ASAP3 is colored pink. C, comparison of the predicted electrostatic surfaces of the different ANK domains. The ribbon representation of the ANK domain of ACAP1 is shown for orientation guidance. The electrostatic surfaces of the different ANK domains are shown, with negatively charged regions colored red and positively charged regions colored blue.