SinR repressor/SinI anti-repressor, dimerisation domain (IPR010981)

Short name: SinR/SinI_dimer_dom

Overlapping homologous superfamilies

Domain relationships



The SinR repressor is part of a group of Sin (sporulation inhibition) proteins in Bacillus subtilis that regulate the commitment to sporulation in response to extreme adversity [PMID: 9799632]. SinR is a tetrameric repressor protein that binds to the promoters of genes essential for entry into sporulation and prevents their transcription. This repression is overcome through the activity of SinI, which disrupts the SinR tetramer through the formation of a SinI-SinR heterodimer, thereby allowing sporulation to proceed. The SinR structure consists of two domains: a dimerisation domain stabilised by a hydrophobic core, and a DNA-binding domain that is identical to domains of the bacteriophage 434 CI and Cro proteins that regulate prophage induction. The dimerisation domain is a four-helical bundle formed from two helices from the C-terminal residues of SinR and two helices from the central residues of SinI. These regions in SinR and SinI are similar in both structure and sequence. The interaction of SinR monomers to form tetramers is weaker than between SinR and SinI, since SinI can effectively disrupt SinR tetramers.

This entry represents the dimerisation domain in both SinI and SinR proteins.

GO terms

Biological Process

GO:0006355 regulation of transcription, DNA-templated

Molecular Function

GO:0046983 protein dimerization activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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