The structure of human carbonic anhydrase II in complex with bromide and azide

Abstract
The three‐dimensional structure of human carbonic anhydrase II complexed with azide and with bromide was investigated crystallographically. Both of these non‐protonated inhibitors replace the zinc and the ‘deep’ water, two catalytically important water molecules in the active site of the molecule. Both the azide and the bromide ions bind in a distorted tetrahedral manner 0.4 and 1.1 Å from the zinc water position, respectively, but are in close contact (2.0 and 2.6 Å, respectively) with the zinc ion.