1DXZ:
reference: Spatial structure of the M2 transmembrane segment of the nicotinic acetylcholine receptor alpha-subunit., Pashkov VS, Maslennikov IV, Tchikin LD, Efremov RG, Ivanov VT, Arseniev AS, FEBS Lett 1999 Aug 20;457(1):117-21. PMID: 10486576

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