Recognition sites of monoclonal antibodies A4 and A24 in the alpha-latrotoxin molecule

alpha-latrotoxin (alpha-LTX) binding sites to functionally active monoclona l antibodies (MA) A4 and A24 were localized using three approaches: hydroly sis of the toxin followed by the N-terminal sequencing of immunoreactive pe ptides; the study of antibody interaction with several recombinant alpha-LT X fragments; and Western immunoblotting of synthetic overlapping peptides ( 6-8 aa) whose structures correspond to that of the immunoreactive alpha-LTX fragment. It was shown that the MA A4 epitope is located within the F-234- M-294 protein fragment and that of MA A24 interacts with the fragment (FDKD IT352)-F-347.