Domain

SANT domain (IPR017884)

Short name: SANT_dom

Domain relationships

Description

The SANT domain is a motif of ~50 amino acids present in proteins involved in chromatin-remodelling and transcription regulation. This eukaryotic domain was identified in nuclear receptor co-repressors and named after switching-defective protein 3 (Swi3), adaptor 2 (Ada2), nuclear receptor co-repressor (N-CoR) and transcription factor (TF)IIIB [PMID: 8882580]. Although SANT domains show remarkable sequence and structural similarity to the DNA-binding helix-turn-helix (HTH) domain of the myb-like tandem repeat, their function is not DNA binding. Instead, SANT domains are protein-protein interaction modules and some can bind to histone tails (e.g. in Ada2 and SMRT). The SANT domain has been proposed to function as a histone-interaction module that couples histone-tail binding to enzyme catalysis for the remodelling of nucleosomes [PMID: 14536084, PMID: 15040448].

SANT domains are found in combination with other domains, such as the SWIRM domain (IPR007526), the ZZ-type zinc finger (see IPR000433), the C2H2-type zinc finger, the GATA-type zinc finger (IPR000679), the MPN-domain and DEAH ATP-helicase domain.

The 3-dimensional structure of the SANT domain forms three alpha helices [PMID: 14536084] similar to the DNA-binding myb-type HTH domain. Because of the strong resemblance, the SANT domain can also be detected as a myb-like "DNA-binding" domain. Most SANT domains have acidic amino acids at the start of helix 2 and in helix 3, while myb-like DNA-binding domains have more positively charged residues, in particular in their third 'recognition' helix. The bulky aromatic and hydrophobic residues in the centre of helix 3 that are incompatible with DNA contacts of myb-like DNA-binding domains form another distinguishing property of SANT domains.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles