Genetically Engineered Pores Sensing Metal Ions

摘要

Stochastic sensing with pore-forming proteins has been established as a means for sensing metal ions by using engineered forms of alpha-hemolysin as the sensor elements. The alpha-hemolysin pore is a heptamer, which has disadvantages for certain manipulations in protein engineering. 1' Therefore a single-chain protein pore was sought. In this work, the Escherichia coli outer membrane protein, OmpG, was shown to be a monomeric, single-chain molecule. The availability of milligram amounts of this porin will be useful for membrane protein engineering studies that will yield stochastic sensing elements more diverse than those previously accessible. Analyte- responsive pores are an inherently powerful technology for the real-time quantification of nanomolar levels of essential or toxic metal ions. Genetically engineered pores can be tailored for sensitivity, selectivity, resistance to fouling and other important characteristics. For many metal ions, the response time is limited only by analyte diffusion.