SinR is a pleiotropic regulator of several late growth processes. It is a tetrameric DNA binding protein whose activity is down-regulated thorough the formation of a SinI:SinR protein complex. When complexed with SinI, the SinR tetramer is disrupted such that is no longer able to bind DNA.

1: SinI modulates the activity of SinR, a developmental switch protein of Bacillus subtilis, by protein-protein interaction. Bai U, Mandic-Mulec I, Smith I; Genes Dev. 1993;7:139-148. PMID:8422983

2: Crystallisation of the Bacillus subtilis sporulation inhibitor SinR, complexed with its antagonist, SinI. Lewis RJ, Brannigan JA, Smith I, Wilkinson AJ; FEBS Lett. 1996;378:98-100. PMID:8549812