Figure 5.

Constitutive expression of CopM partially restores copper resistance of COPR mutant strain. (A) Western blot analysis of CopM levels after copper addition in WT, WTM, COPR, and COPRM strains. Cells were grown in BG11C-Cu medium to mid-log growth phase and exposed for 4 h to 1 μmol/L copper. Five micrograms of total protein from soluble extracts was separated by 15% SDS-PAGE and analyzed by western blot to detect CopM and GSI. (B) Phenotypic characterization of mutant strains affected in cop genes. Tolerance of WT, WTM, COPR, and COPRM strains to copper was examined. Ten-fold serials dilutions of a suspension of 1 μg chlorophyll mL⁻¹ cells grown to mid-log phase were spotted onto BG11C-Cu supplemented with the indicated copper concentrations. Plates were photographed after 5 days of growth.