Fig 3.

Heterologous expression and verification of functional membrane insertion of AaSAMT. (A and B) Proteins of the E. coli membrane fraction (25 μg per lane) were separated by SDS-PAGE (A), and the presence of recombinant AaSAMT was verified by immunodetection (B). Lanes: M, molecular mass marker (in kDa); 1, total membrane proteins of noninduced E. coli cells harboring the AaSAMT-pET16b expression vector; 2, total membrane proteins from E. coli expressing AaSAMT. (C) Time dependency of AaSAMT-catalyzed uptake of radioactively labeled [methyl-¹⁴C]SAM. IPTG-induced (◆) and noninduced (▩) E. coli cells were incubated with 10 μM ¹⁴C-labeled SAM, and import was stopped at the indicated times by removal of external substrates via vacuum filtration and washing. Data are the means of data from three independent experiments, each with two technical replicates. Standard errors are displayed.