3.5.1.23 | Ca2+ |
ACER3 has a catalytic Zn2+ binding site in its core and a Ca2+ binding site physically and functionally connected to the Zn2+, two residues appear to play critical roles in physically linking the Ca2+ and the Zn2+ sites, W20 and E33. E33 carboxylate interacts with the Ca2+ ion and is in close proximity to H81TM2 side chain, while H81TM2 coordinates the Zn2+, Ca2+-binding site within the N-terminus, structure overview. The Ca2+ ion is coordinated by six oxygens from the D19 carboxylate (bidentate), the W20 backbone carbonyl, the E22 backbone carbonyl, the N24 side chain carbonyl, and the E33 carboxylate (monodentate) |
754856 |