Figure 3.

Levan synthesis phenotype of E. coli BL21(DE3) expressing wild-type Lsc3 and alanine replacement mutants of the catalytic triad amino acids. Transformants were streaked onto MacConkey + Amp medium containing 10% sucrose and 1 mM IPTG to induce the T7 polymerase and grown at 37 °C (see Section 3.2).