A novel acetate-bound complex of human carbonic anhydrase II.
The enzyme human carbonic anhydrase II (hCAII) crystallized in an acetate-bound
complex belonging to space group P2(1)2(1)2(1), with unit-cell parameters a =
42.3, b = 71.8, c = 74.0 A. The structure was solved by the
molecular-replacement method and refined to an R value of 0.18 and an R(free) of
0.21. The acetate molecule replaced the zinc-bound water molecule in the
structure, differing from previous reports regarding the site of acetate
binding. This mode of binding disrupts the hydrogen-bonded solvent network
required for activity of the enzyme. This mode of inhibitor binding is a novel
one that has not been observed previously.