did anyone use or have experience with the E. coli strain LOBSTR. It should reduce the background of E. coli proteins which bind to Ni or Co in IMAC.
Joop van den Heuvel
We tested LOBSTR for the expression of a protein that we were purifying under denaturing conditions (8M urea). With regular BL21 we always saw a band at about the size of the SlyD E. coli protein, and this was confirmed via mass spec. We could not separate it from our target. We then tried expression in LOBSTR and the band was completely gone. So at least for SlyD contamination under these conditions it helped a lot.
Interestingly, the expression of the protein was also better in LOBSTR, but we could not reproduce this with two other proteins we tried so I think this was somehow protein dependent. We did not do any more rigorous comparisons.