Engineering protein pores for biosensing

Engineered protein pores can be used as stochastic sensors for single-molecule detection (Fig. 1). The ionic current flowing through a pore under an applied potential is altered when an analyte binds within the lumen. The frequency of the binding events allows the determination of the concentration of an analyte, while the nature of the events (e.g. their amplitude or duration) enables analyte identification. Compare to other approaches, the stochastic sensing has an advantage of being sensitive (nanomolar concentrations), fast (up to microsecond resolution), and without delays from mixing and diffusion (real-time).

A quiet outer membrane protein G (qOmpG) from E. coli is a good candidate for use as sensor elements due to its monomeric feature. My research focus on the development of the utility of qOmpG in the following respects:

1. to enlarge the spectrum of molecules sensed by qOmpG, the properties of the pore will be tailored by site-direct mutagenesis. Different molecular adapters, which bind to the pore lumen and provide a binding site for analytes will be selected for the detection of variant analytes.
2. to use the qOmpG sensor for the detection of biological macromolecules, such as proteins and DNA.
3. to couple an enzyme to the qOmpG to study the single-molecular enzymatic reaction
4. to use qOmpG pore as a model system with which to gain insights into important biological processes such as transmembrane polymer translocation (e.g. DNA, polysaccharides) or nutrient uptake (e.g. sugars, amino acids).