This is a permuted version of a single unit of the zf-CXXC domain that is detected in the Demeter-like proteins of land plants. Structural comparisons show that the mono-CXXC is homologous to the structural-zinc binding domain of medium chain dehydrogenases [1]. The classical zf-CXXC domain binds nonmethyl-CpG dinucleotides.

1: Natural history of eukaryotic DNA methylation systems. Iyer LM, Abhiman S, Aravind L; Prog Mol Biol Transl Sci. 2011;101:25-104. PMID:21507349