SEARCH Articles Figures Tables A schematic representation of the seven transmembrane helical peptide chains viewed from inside the cell. The numbering denotes the first and last amino acid residues. The proton channel is believed to be the volume between helices C, D, F and G [Publishers Imprint] See Also: A schematic representation of the seven transmembrane helical peptide chains viewed from inside the cell. The numbering denotes the first and last amino acid residues. The proton channel is believed to be the volume between helices C, D, F and G