Review Article

Neurochemical and Behavioral Features in Genetic Absence Epilepsy and in Acutely Induced Absence Seizures

Figure 2

Probable transmembrane topology of HCN channels. Six transmembrane domains (S1–S6) of monomeric of the HCN1 subunit are presented. Five endogenous cysteine residues are localized in transmembrane domains of all four isoforms of HCN channels. Three of them in the 303, 318, and 347 position (Cys303, Cys318, and Cys347) are localized closer to the extracellular space, whereas the two remaining ones (Cys298 and Cys374) are probably closer to the cytoplasmic or inner side. The cyclic nucleotide-binding domain (CNBD) is localized on the C-terminus. The glycine-tyrosine-glycine amino-acid sequence forms a channel pore between the S5 and S6 domains (with permission from Springer, [30]).
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