Table 4. Electrostatic potential at the Br-binding site.

CAs	Potential at Br-binding site, kT/e
dCA II	11.0
hCA II	19.9
hCA I	20.0
nCA	20.0
hCA IV	17.5
bCA II	23.3
hCA XII	24.5

The definition and coordinates of the Br-binding site are as described in the text. The coordinates for the various CAs were determined by superimposing the respective structures on the structure of hCA II complexed with Br (Protein Data Bank ID Code IRAZ) (22). The approximate location of the Br-binding site corresponds to the Zn-bound water (Wat in Fig. 8a). The average potential [kT per electron (e)] for 720 points within 0.2 Å around the Br-binding coordinate was calculated as described in Materials and Methods.