Probing the effect of the outer saccharide residues of N-linked glycans on peptide conformation.

The disulfide bond between residues Cys128 and Cys142 that closes this conserved extracellular loop is also critical for the structural integrity of the receptor complex; mutation of the cysteine residues 3 or expression of the protein in the presence of reducing agents 4 severely impacts the oligomerization of the protein complex. In addition, this loop includes a conserved proline residue at position 136 that is required for nAChR folding and assembly. 5