This domain is found at the C-terminal of Clr3 (Cryptic loci regulator 3) also known as histone deacetylase clr3 (EC:3.5.1.98). Structure analysis reveals that the Arb2 domain has clear homology to alpha/beta-hydrolases but that it is lacking the catalytic triad of these enzymes. Functional studies show that the Arb2 domain is necessary for centromeric heterochromatin silencing suggesting a model where the Arb2 domain, through residues N562 and Y563, acts as an anchor that connects the HDAC activity of Clr3 to the SHREC complex. SHREC (Snf2/Hdac Repressive) complex in fission yeast drives transcriptional gene silencing in heterochromatin [1].

1: SHREC Silences Heterochromatin via Distinct Remodeling and Deacetylation Modules. Job G, Brugger C, Xu T, Lowe BR, Pfister Y, Qu C, Shanker S, Banos Sanz JI, Partridge JF, Schalch T; Mol Cell. 2016;62:207-221. PMID:27105116