pfam15613: WSD (This model is not part of the current CDD release)
Williams-Beuren syndrome DDT (WSD), D-TOX E motif
This family represents the combined alpha-helical module found in diverse eukaryotic chromatin proteins. Based on the Ioc3 structure, the N-terminus of this module is inferred to interact with nucleosomal linker DNA and the SLIDE domain of ISWI proteins. The resulting complex forms a protein ruler that measures out the spacing between two adjacent nucleosomes. The acidic residue from the GxD signature at the N-terminus is a major determinant of the interaction between the ISWI and WHIM motifs. The N-terminal portion also contacts the inter-nucleosomal linker DNA. The module shows a great domain architectural diversity and is often combined with other modified histone peptide recognizing and DNA binding domains, some of which discriminate methylated DNA. The WSD module constitutes the inter-nucleosomal linker DNA binding site in the major groove of DNA, and was first identified as WSD, the D-TOX E motif of plant homeodomains homologous with the mutant transcription factor causing Williams-Beuren syndrome in association with the DDT-domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",