FIGURE 2.

Substitutions at Lys¹⁵⁵ of CfNT2 confer adenosine transport activity. Purine auxotrophic yeast cells (Δade2) expressing the indicated ORFs under the control of the yeast CUP1 promoter were grown on SD ura⁻ ade⁻ medium supplemented with 100 μm CuSO₄ and inosine (A), adenosine (B), or adenosine and guanosine (C) as purine source(s). Plates were photographed after 3 days of growth at 30 °C.