repeat 1 of the paired tandem chromodomains of chromodomain helicase DNA-binding protein 3 and 4, and similar proteins
Repeat 1 of tandem CHRomatin Organization Modifier (chromo) domains, found in CHD (chromodomain helicase DNA-binding) proteins such as mammalian helicase DNA-binding proteins CHD3 and CHD4. The CHD proteins belong to the SNF2 superfamily of ATP-dependent chromatin remodelers and contain two signature motifs: a pair of chromodomains located in the N-terminal region, and the SNF2-like ATPase domain located in the central region of the protein. CHD chromatin remodelers are important regulators of transcription and play critical roles during developmental processes. The N-terminal chromodomains of CHD1 have been shown to guard against sliding hexasomes. Mutations in the chromodomains of mouse CHD1 result in nuclear redistribution, suggesting that the chromodomain is essential for proper association with chromatin; also, deletion of the chromodomains in the Drosophila melanogaster CHD3-4 homolog impaired nucleosome binding, mobilization, and ATPase functions. Human CHD3 (also named Mi-2 alpha) and CHD4 (also named Mi-2 beta) are coexpressed in many cell lines and tissues and may act as the motor subunit of the NuRD complex (nucleosome remodeling and deacetylase activities). The proteins form distinct CHD3- and CHD4-NuRD complexes that repress, as well as activate gene transcription of overlapping and specific target genes. A chromodomain is a conserved region of about 50 amino acids, found in a variety of chromosomal proteins, and which appears to play a role in the functional organization of the eukaryotic nucleus. The chromodomain is implicated in the binding, of the proteins in which it is found, to methylated histone tails and maybe RNA. A chromodomain may occur as a single instance, in a tandem arrangement, or followed by a related chromo shadow domain.
Feature 1:peptide binding site [polypeptide binding site]
Evidence:
Comment:based on the contacts of the first repeat (CD1) of tandem chromodomains of human CHD1, with histone H3 tail containing trimethyllysine 4 and dimethylarginine 2; human CHD1 uses 2 aromatic residues (tryptophans) for methyllysine recognition
Jiyao W et al.(2023). "The conserved domain database in 2023.",