Chemical and Biological Sensing Utilizing Fused Bacteriorhodopsin Protein Hybrids

This paper describes how monomeric bR can be overproduced in Escherichia coli and subsequently utilized as an integral component of a generic, nanoscale chemical sensing platform. The utility of this sensing platform is that it can be adapted for detection of a wide range of biological and chemical agents at, or below, nanomolar concentration levels. The gene encoding for bacteriorhodopsin has been successfully isolated from Halobacterium salinarum strain S9P using a colony-level PCR approach. Utilizing this purified DNA and a plasmid expression vector system, a fused protein hybrid consisting of maltose binding protein and bacterio-opsin has been expressed in transformed E. coli. The fusion hybrid has been purified in soluble form from E. coli cellfree extracts at up to 70mg/L. Renaturation studies to incorporate all-trans retinal within the bacterio-opsin protein are currently underway.