THE MONGOOSE ACETYLCHOLINE-RECEPTOR ALPHA-SUBUNIT - ANALYSIS OF GLYCOSYLATION AND ALPHA-BUNGAROTOXIN BINDING

The mongoose AChR alpha-subunit has been cloned and shown to be highly homologous to other AChR alpha-subunits, with only sis differences in amino acid residues at positions that are conserved in animal species that bind alpha-bungarotoxin (alpha-BTX). Four of these six substitut ions cluster in the ligand binding site, and one of them, Asn-187, for ms a consensus N-glycosylation site. The mongoose glycosylated alpha-s ubunit has a higher apparent molecular mass than that of the rat glyco sylated alpha-subunit, probably resulting from the additional glycosyl ation at Asn-187 of the mongoose subunit, The in vitro translated mong oose alpha-subunit, in a glycosylated or non-glycosylated form, does n ot bind alpha-BTX, indicating that lack of alpha-BTX binding can be ac hieved also in the absence of glycosylation. (C) 1998 Federation of Eu ropean Biochemical Societies.