Glutamine-rich N-terminal helical domain of HDAC9, a Class IIa histone deacetylase
This family consists of the glutamine-rich domain of histone deacetylase 9 (HDAC9). It belongs to a superfamily that consists of the glutamine-rich N-terminal helical extension to certain Class IIa histone deacetylases (HDACs), including HDAC4, HDAC5 and HDCA9; it is missing from HDAC7. This domain confers responsiveness to calcium signals and mediates interactions with transcription factors and cofactors, and it is able to repress transcription independently of the HDAC C-terminal, zinc-dependent catalytic domain. It has many intra- and inter-helical interactions which are possibly involved in reversible assembly and disassembly of proteins. HDACs regulate diverse cellular processes through enzymatic deacetylation of histone as well as non-histone proteins, in particular deacetylating N(6)-acetyl-lysine residues.
Comment:based on the structure of the N-terminal glutamine-rich domain of human histone deacetylase 4 (HDAC4); four copies of HDAC4 form a four-helix bundle
Comment:The interactions of each helix with its neighboring three helices are the same for all four helices due to the D2 point group symmetry.
Jiyao W et al.(2023). "The conserved domain database in 2023.",