Hi Gloria,
Just to follow up Zhijie's email. We use E.coli expressed ULP1 protease extensively in my lab, and it's very active and quite a bit cheaper than the commercial version. My last prep from 2L produced greater than 50mg, and I've more or less froze it directly off of the NiNTA elution. I keep my his-tag on my protease and easy to clean up after using it.
-john
On May 24, 2012, at 2:41 PM, Gloria Borgstahl wrote:
> My fellow crystallographers,
> We are thinking the SUMO/His vectors would be nice to have in the lab
> aresenal... but. The stumbling block is that the protease needed for
> cleavage is very expensive at crystallography scale. SUMO(ULP-1)
> protease costs ~$700/mg fusion protein. It would not be a problem
> for labs using micrograms of protein, but is prohibitive at our level
> of protein purification.
> Has anyone found a way around this? Your pal, Gloria
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