Tellurite reductase expression experiments were carried out as recently published , with one modification: 100 µg/mL chloramphenicol was used for strain RB 16-17 instead of tetracycline. Detection of TeO32− reduction in cell extracts and localization of reductase activity was performed as described . Rate of reduction (1 unit equal to 1 µg tellurite reduced/µg protein/h) was calculated for each cellular fraction. For isolation of membranes, cells were broken by French Press and centrifuged at 20,000 rpm for 1 h to remove debris. The supernatant was collected and ultracentrifuged at 60,000 rpm for 12 h. The membrane pellet was then washed with 10 mM Tris HCl, pH 8.0. Membranes were resuspended in their respective growth media containing K2TeO3.