Effect of induction temperature on MaSp2-64mer expression by E. coli
BL21(DE3) cells harboring pET28a-MaSpII64 in LB medium. Initial cultivation temperature
was 30 ◦C; and 1 mM IPTG was added at OD600 of ∼0.4, and incubated for
additional 6 h at an indicated temperature. Protein samples of cell lysates were separated
on 10% SDS-PAGE gels and the arrow indicates the target silk protein (A). The
cell cultures without IPTG treatment (open bar) and those induced at either 16 ◦C
(grey bar) or 30 ◦C (black bar) were sampled and subjected to plasmid maintenance
assay (B). Error bars represent standard deviations from the mean values of three
replicates.