RECOGNITION OF THE COLICIN-A N-TERMINAL EPITOPE 1C11 INVITRO AND INVIVO IN ESCHERICHIA-COLI BY ITS COGNATE MONOCLONAL-ANTIBODY

We demonstrate that the 1C10 monoclonal antibody (mAb) directed agains t the N-terminal domain of the colicin A recognizes a 13 residue-regio n (13 ly-Trp-Ser-Ser-Glu-Arg-Gly-Ser-Gly-Pro-Asp-Pro25). When this pep tide is inserted into a protein in the amino-terminal or an internal p osition, the tagged protein is efficiently detected by the 1C11 mAb ei ther by immunoblotting or immunoprecipitation. In vitro, the minimal s tructure required for detection using the pepscan system is 19Arg-Gly- Ser-Gly-Pro-Glu-Pro25, indicating that in vivo the proper exposure of the epitope requires additional residues. The construction of a versat ile vector allowing overproduction of tagged proteins is described. Va rious applications of the 1C11 epitope are mentioned. This epitope did not alter the function of any of the proteins so far tested.