Using BIACORE as Pots and Pans
We expressed a recombinant protein tagged with Hisx6, using E. coli. Jimmy, one of our postgraduate students, said that his preliminary experiment suggested that active recombinant protein could be produced after induction by IPTG at lower temperature over a long period. So we took 10 µl lysate of culture medium before and after the induction, diluted 10-fold, and injected it on a Sensor Chip NTA on which Ni2+ was chelated (see figure). We could see a binding curve for the lysate taken after the induction, and this was precluded by imidasol. It was working, so we next sampled to look at expression levels over time and at different temperatures. The only alternative method to BIACORE was Western blotting (because there was not a high enough expression level, the band corresponding to the recombinant could not be determined using only SDS-PAGE).