Conserved Site

HMG box A DNA-binding domain, conserved site (IPR017967)

Short name: HMG_boxA_CS


High mobility group (HMG or HMGB) proteins constitute a family of relatively low molecular weight non-histone components in chromatin. HMG1 and HMG2 are highly similar, and preferentially bind single-stranded DNA and unwind double-stranded DNA. Although they have no sequence specificity, they have a high affinity for bent or distorted DNA, and bend linear DNA. HMG1 and HMG2 contain two DNA-binding HMG-box domains (A and B) that show structural and functional differences, and have a long acidic C-terminal domain rich in aspartic and glutamic acid residues. The acidic tail modulates the affinity of the tandem HMG boxes in HMG1 and 2 for a variety of DNA targets. HMG1 and 2 appear to play important architectural roles in the assembly of nucleoprotein complexes in a variety of biological processes, for example V(D)J recombination, the initiation of transcription, and DNA repair [PMID: 11497996].

This signature identifies HMG box A, which is only found in HMG 1 and 2 proteins whereas the HMG box B is also present in various transcription factors. HMG boxes have unusual DNA binding activity. They bind preferentially to distorted DNAs, such as four-way junctions, kinked cisplatin-modified DNA, DNA bulges, and have the property to bend DNA [PMID: 11497996]. They can bind DNA without sequence specificity like in HMG1 and 2 or recognise a specific site.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003677 DNA binding

Cellular Component

GO:0005634 nucleus

Contributing signatures

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