FIG. 1.

CzcD functionally complements a ΔzitB::Cm zntA::Km E. coli strain. (A) Accumulation of ⁶⁵Zn²⁺ by E. coli GG48 (ΔzitB::Cm zntA::Km) (○) and strain GG48 containing the czcD gene (•) was determined by the filtration method with 15 μM zinc chloride. The arrow indicates when 10 μM FCCP was added to cells containing the czcD gene (gray circles). ♦, zinc uptake by W3110 wild-type cells. (B) Accumulation of ¹⁰⁹Cd²⁺ (□ and ▪), ⁵⁷Co²⁺ (▵ and ▴), or ⁶³Ni²⁺ (▿ and ▾) by E. coli GG48 (ΔzitB::Cm zntA::Km) (open symbols) and strain GG48 containing the czcD gene (solid symbols), as determined at a metal cation concentration of 15 μM as described above. Mean values of duplicate determinations are shown; the error bars indicate standard deviations. d.w., cellular dry weight.