Spatial structure of the M2 transmembrane segment of the nicotinic acetylcholine receptor alpha-subunit

A synthetic peptide corresponding to the transmembrane segment M2 (residues 236-267) of the a-subunit of the nicotinic acetylcholine receptor from Tor pedo californica has been studied by two dimensional H-1-NMR spectroscopy i n a chloroform-methanol (1:1) mixture containing 0,1M LiClO4. Reconstructio n of the spatial structure of M2 from the NMR data resulted in an a-helix f ormed by residues 241-263. Distribution of the molecular hydrophobicity pot ential on the helix surface is very similar to that in five-helix bundles o f proteins with a known three dimensional structure: two hydrophilic bands located on the opposite helix sides separated by strong hydrophobic zones, (C) 1999 Federation of European Biochemical Societies.