This domain is found in eukaryotes, and is approximately 90 amino acids in length. The family is found in association with Pfam:PF00850. The domain forms an alpha helix which complexes to form a tetramer. The glutamine rich domains have many intra- and inter-helical interactions which are thought to be involved in reversible assembly and disassembly of proteins. The domain is part of histone deacetylase 4 (HDAC4) which removes acetyl groups from histones. This restores their positive charge to allow stronger DNA binding thus restricting transcriptional activity.

1: Crystal structure of a conserved N-terminal domain of histone deacetylase 4 reveals functional insights into glutamine-rich domains. Guo L, Han A, Bates DL, Cao J, Chen L; Proc Natl Acad Sci U S A. 2007;104:4297-4302. PMID:17360518