Transmembrane helices, serotonin

Numerous site-directed mutagenesis studies have provided a conclusive picture for the molecular interactions between the receptor-activating biogenic amines (e.g. serotonin, epinephrine, dopamine) and their receptors [23-27] a highly conserved aspartate residue in transmembrane (TM) helix TM3 (Asp 3.32 according to the Ballosteros-Weinstein nomenclature) [28], conserved serine residues in TM5 (e.g. 

Figure 4 Schematic representation of predicted neurotransmitter binding sites A dopamine B adrenaline C acetylcholine D serotonin. Helix axes are represented as vertical lines and numbered 1 to 7. Residues surrounding the neurotransmitter are schematically displayed and numbered in a coded manner the first digit indicates the transmembrane domain an the next two digits correspond to the rank of the residue in this domain (reproduced with the authorisation of the authors and publishers, from Medecine/Science 1993, 9, 31-40.).

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