[ccp4bb] Zinc binding protein expressed from insect cells

2014-08-15 Thread Harvey Rodriguez
Dear all, Sorry for the non-crystallographic question. Currently I am working on a zinc binding protein which is expressed in insect cells and may contain 4-6 zinc ions. As we know, so many zinc binding proteins can absorb the iron ions from the culture medium and the protein looks from yellow to

[ccp4bb] protein lost activity after size exclusion chromatography

2011-03-16 Thread Harvey Rodriguez
Dear all, Recently, I came across an obstacle on the purification and acitivty measurement of my protein. My protein was expressed with an C terminal His tag in the HEK 293T cells and purified by nickel affinity, anion exchange and size exclucion chromatography. For every purification step, I