Probably part of a deoxycholate transport system. Its expression in the presence of deoxycholate in a ygiS deletion mutant increases intracellular deoxycholate levels and decreases cell growth; higher expression in the presence of deoxycholate inhibits cell growth completely. Bile acid detergents such as deoxycholate are important for host defense against bacterial growth in the gall bladder and duodenum. Repressed by the toxin-antitoxin system MqsR-MqsA; this mRNA is degraded by mRNA interferase MqsR. Cells grow better in the presence of the bile acid deoxycholate. Increased membrane stability when incubated for 2 hours in the presence of 4.5% deoxycholate. Increased cell survival in the presence of 20% deoxycholate. Belongs to the bacterial solute-binding protein 5 family.