TABLE 2

Distributions of conserved and type I and/or II sites among the CAs

Functionally
important
positions
Other
positions
Totals
A.
    Conserved sites13 (6.7)34 (40.3)47
    Other sites18 (24.3)151 (144.7)169
    Totals31185216
B.
    Type I and/or II sites11 (6.0)33 (38.0)44
    Other sites18 (23.0)151 (146.0)169
    Totals29184213
  • Type I and/or II sites are not included in A, whereas conserved positions are conversely excluded from B. Expected counts are given in parentheses. Functionally important positions refer to the 42 residues of the active site and N terminus for AE1 binding and/or proton shuttling. The chi-square tests for both contingency tables are significant (P = 0.005 and 0.017, respectively).