I've been purifying 8 proteins of the same family using E Coli and standard vector with IPTG induction (pGEX, pMAL, etc), plus their point-mutated versions. Also, I have been purifying some other MBP tagged random protein for labmates.
Based on these proteins, honestly I could find no "general rule" for growing them, even for those that are closely related one grow at low temp, others grow at 37C, one must be induced with low IPTG, the other must be at high IPTG, some protein "behaves" well i.e. it isn't degraded fast, other proteins are difficult i.e. it degraded in the cell or in ice.
How are you going to get "good" at purifying protein, if there are so so many variables in preps? (good and efficient, e.g. by just predicting from its sequence you have general idea of what temp to grow, what induction, knowing what buffer to use, how fast, etc)
Or in reality there is no way to be "good" like I said above, and treat them as unique. Therefore everytime with new protein I have to:
1. read manual/papers that have purified them to determine strategy
2. from (1), do small scale growing/induction experiment to determine which is good, western blot
3. from (1 and 2), do small scale prep with diff buffers (e.g. use buffers that contain MgCl2 for protein that has been predicted to use it, vs no MgCl2)
4. rinse and repeat
Edited by MyProteinBulliedMe, 29 December 2010 - 12:48 AM.