Alpha-bungarotoxin molecules and uses thereof

Abstract

This invention relates to compositions and methods for the specific inhibition of neurotransmission. More specifically, the invention relates to isolated modified α-bungarotoxin molecules that show high specificity for nicotinic acetylcholine receptors. Such modified α-bungarotoxin molecules, as well as native α-bungarotoxin molecules, are useful in a variety of conditions where localized inhibition of neuronal and/or muscle cell function is desirable.

We claim:  
     
         1 . An isolated polypeptide which selectively binds nicotinic acetylcholine receptors with a non-native specificity, comprising the amino acid sequence of SEQ ID NO:2 having at least one amino acid substitution, or a fragment thereof.  
     
     
         2 . The isolated polypeptide of  claim 1 , wherein the at least one amino acid substitution is selected from the group consisting of a substitution at amino acid 38 and a substitution at amino acid 42 of SEQ ID NO:2.  
     
     
         3 . The isolated polypeptide of  claim 2 , wherein the at least one amino acid substitutions are selected from the group consisting of Pro at amino acid 38 and Gln at amino acid 42 of SEQ ID NO:2.  
     
     
         4 . The isolated polypeptide of  claim 3 , comprising the amino acid sequence of SEQ ID NO:2 having amino acid substitutions of Pro at amino acid 38 and Gln at amino acid 42.  
     
     
         5 . A pharmaceutical composition comprising the isolated polypeptide of  claim 1 , and a pharmaceutically acceptable carrier.  
     
     
         6 . The pharmaceutical composition of  claim 5 , comprising a pharmaceutically effective amount of the isolated polypeptide of  claim 1 .  
     
     
         7 . A pharmaceutical composition comprising an isolated native α-bungarotoxin, and a pharmaceutically acceptable carrier.