A two-hybrid system based on chimeric operator recognition for studying protein homo/heterodimerization in Escherichia coli

The development of a convenient and promising alternative to the various tw o-hybrid methods that are used to study protein-protein interactions is des cribed. In this system, a lambdoid chimeric operator is recognized by a hyb rid repressor formed by two chimeric monomers whose C-terminal domains are composed of heterologous proteins (or protein domains). Only if these prote ins efficiently dimerize in vivo is a functional repressor formed able to b ind the chimeric operator and shut off the synthesis of a downstream report er gene, This new approach was tested with several interacting proteins ran ging in size from less than 100 to more than 800 amino acids and, to date, no size or topology limit has been detected.