We recommend NEBExpress Competent E. coli (NEB #C2523). This is an E. coli B strain similar to T7 Express and BL21 (DE3), except that it lacks the T7 RNA Polymerase (the pMAL vectors use the E. coli RNA Polymerase). NEB Express, T7 Express (NEB #C2566), BL21 (NEB #C2530) and BL21(DE3) (NEB #C2527) Competent E. coli all give similar results – the presence of the T7 RNA Polymerase doesn't seem to have any effect. Other successful strains include NEB 10-beta (NEB #C3019) and NEB Turbo (NEB #C2984) Competent E. coli. One can start with NEB Express, or with whatever competent cells are readily available, and then try another strain if a problem with expression or purification develops.
Find a Golden Butterfly for a Chance to Win!
Help us celebrate our 50th anniversary! We have hidden 1,000 golden butterflies and are waiting for you to find them. They can be anywhere that you find NEB! Beginning April 15th, be sure to visit our website and tables at tradeshows and events you are attending. Visit our social media channels frequently for tips on where we have hidden the butterflies – and once you find one, either click or scan the code to be eligible for a 50th anniversary prize pack, as well as a grand prize trip to NEB headquarters in Ipswich, MA!.
