A colleague of mine is trying to purify His-tagged fusion proteins
from E.coli (BL21 DE3) by Ni-NTA affinity chromatography under
denaturing conditions. The method she's following recommends lysing
the bacteria by resuspending the pellet in 6M guanidine HCl.
After pelleting undissolved material, she ran aliquots of pellet and
supernatant on SDS-PAGE, and found that there appeared to be
incomplete lysis of the cells. Has anyone out there experience of
this? What did you do to improve cell lysis? Sonication? Pre-treatment
with lysozyme? Any iodeas?
Thanks in advance
Andy Phillips (andy.phillips at bbsrc.ac.uk)