Table 2. Effect of sodium arsenite on the activity of seHAS Cys mutants.

E. coli membranes containing wildtype seHAS or the indicated double or triple Cys-mutants were incubated in PBS with or without 10 mM sodium arsenite at 4°C for 1 h. The activity of seHAS was then determined in triplicate as described in Methods. The values shown are the mean ± SEM inhibition relative to the no sodium arsenite treatment controls based on two experiments (n=6) for the double mutants or one experiment (n=3) for the single mutants (n=9 for wildtype).

seHAS Mutant	Inhibition (%)
C(226,262)A	19 ± 1
C(226,281)A	2 ± 1
C(226,367)A	45 ± 5
C(262,281)A	9 ± 3
C(262,367)A	8 ± 1
C(281,367)A	5 ± 3
Δ3C(C226)	3 ± 1
Δ3C(C262)	0.6 ± 0.1
Δ3C(C281)	10 ± 2
Δ3C(C367)	5 ± 1
WT	41 ± 2