BL21

BL21 protein expression bacteria

These bacteria can be transformed with plasmids to express yeast or other proteins for purification. The are all Cloramphenicol resistant, and it is typical to select for transformants in LB + CAM and KAN (depending, of course on the plasmid). Following transformation, these cells can be placed directly into a 50 ml flask of selective media and placed in to the 37C room.

The full name of these bacteria:

BL21 (DE3) pLys5 (RIL)

RIL refers to the fact that these bacteria express eukaryotic tRNA genes in order to recognize all codons for arginine (R), isoleucine (I) and leucine (L).