The CLZ domain is the C-terminal leucine-zipper domain of of cyclic nucleotide-gated channel proteins. The CLZ domains form homotypic trimers in solution thus constraining the channel of the CNGs to contain three cyclic nucleotide-gated subunits, CNGA. The CLZ domains formed homotypic parallel 3-helix coiled-coil domains, consistent with their proposed role in regulating subunit assembly [1].

1: Molecular mechanism for 3:1 subunit stoichiometry of rod cyclic nucleotide-gated ion channels. Shuart NG, Haitin Y, Camp SS, Black KD, Zagotta WN; Nat Commun. 2011;2:457. PMID:21878911