Reliable Expression for Toxic Proteins. IG® C43(DE3)pLysS Electrocompetent Cells are designed for high-efficiency transformation and stable expression of toxic or difficult proteins in IPTG-inducible T7 systems. Derived from BL21(DE3), this strain improves tolerance to toxic proteins, while the pLysS plasmid suppresses basal expression to stabilize challenging constructs. Custom formats, custom package sizes and bulk pricing are available upon request.