Monitoring recombinant protein expression in bacteria by rapid evaporative ionisation mass spectrometry

RATIONALE: There is increasing interest in methods of direct analysis mass spectrometry that bypass complex sample preparation steps.
METHODS: One of the most interesting new ionisation methods is rapid evaporative ionisation mass spectrometry (REIMS) in which samples are vapourised and the combustion products are subsequently ionised and analysed by mass spectrometry (Synpat G2-si). The only sample preparation required was the recovery of a cell pellet from a culture that could immediately be analysed.
RESULTS: In this paper, we demonstrate that REIMS can be used to monitor the expression of heterologous recombinant proteins in Escherichia coli. Clear segregation was achievable between bacteria harvesting plasmids that were strongly expressed when compared to other cultures in which the plasmid did not result in the expression of large amounts of recombinant product.
CONCLUSION: REIMS has considerable potential as a near-instantaneous monitoring tool for protein production in a biotechnology environment.