Model systems: Studying molecular recognition using bacterial n-hybrid systems.

Since the first description of the yeast two-hybrid system, related genetic assays for protein-protein interactions have become popular and powerful tools for structure-function analysis on the scale of individual proteins or whole proteomes. After a somewhat surprising lag, similar systems have recently been described for use in bacterial hosts. n-hybrid modifications of the original yeast system have been used to examine interactions with DNA, RNA and small molecules, and other modifications have improved throughput for genomic applications. Bacterial n-hybrid systems are being designed for a similar array of uses. Will the bacterial systems be as popular as the yeast n-hybrid systems? Only time will tell.