SinR is the master regulator that determines whether Bacillus subtilis switches from a free-living, planktonic lifestyle to form a biofilm, a community of cells attached to a surface by an extracellular matrix. Biofilms are an increasing environmental and healthcare issue, causing problems ranging from the bio-fouling of ocean-going vessels, to dental plaque, infections of the urinary tract and contamination of medical instruments such as catheters. SinR inhibits biofilm formation by repressing a number of extracellular matrix-associated operons. The activity of SinR is controlled by the SinR antagonists, SinI, SlrA and SlrR, which interact with SinR to regulate its function. We have combined isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) to determine the thermodynamic and kinetic parameters governing the protein:protein and protein:DNA interactions at the heart of this epigenetic switch. Finally, we present the crystal structure of the SinR tetramer in complex with DNA, revealing the molecular basis of base-specific DNA recognition by SinR and the mode by which SinR activity is controlled by interaction with its antagonists.
Newman JA, Rodrigues C, Lewis RJ Are you the author?
University of Newcastle, United Kingdom.
Reference: J Biol Chem. 2013 Feb 21. (Epub ahead of print)