Fig. 4.

A TIR^EVOLVED is transferable. a Expression levels of scFv^HER2 and FtYfgM⁴⁵⁻¹⁷⁰ using five different signal peptides. In each instance TIR^UNEVOLVED/TIR^EVOLVED pairs were assessed by immuno-blotting. The TIR^EVOLVED had originally been selected for β-lactamase (see Fig. 2). In this experiment, protein production was induced for 2 h, then a volume of cells corresponding to 0.2 OD₆₀₀ units of cells were harvested, separated by a 12% SDS-PAGE and protein levels were determined by immunoblotting with antisera to a poly-histidine tag. ‘Pre’ denotes the precursor form of the protein and ‘Mat’ denotes the mature version