Expression of the α -bungarotoxin Binding Site of the Nicotinic Acetylcholine Receptor by Escherichia coli Transformants

Restriction fragments of DNA derived from a cDNA clone of the α subunit of the acetylcholine receptor were subcloned in Escherichia coli by using the trpE fusion vector, pATH2. Transformants expressing the amino acid sequences 166-315 or 166-200 are shown to produce a chimeric protein that bound α -bungarotoxin. Moreover, it is shown that sufficient amounts of toxin-binding proteins can be generated by individual colonies of bacteria. This provides a new approach for gene selection via functional expression--i.e., ligand overlays of colony blots.