ligand-binding protein LsrB of ABC transporter periplasmic binding protein
Periplasmic binding domain of autoinducer-2 (AI-2) receptor LsrB from Salmonella typhimurium and its close homologs from other bacteria. The members of this group are homologous to a family of periplasmic pentose/hexose sugar-binding proteins that function as the primary receptors for chemotaxis and transporters of many sugar based solutes in bacteria and archaea and that are a member of the type 1 periplasmic binding protein superfamily. LsrB, which is part of the ABC transporter complex LsrABCD, binds a chemically distinct form of the AI-2 signal that lacks boron, in contrast to the Vibrio harveyi AI-2 signaling molecule that has an unusual furanosyl borate diester. Hence, many bacteria coordinate their gene expression according to the local density of their population by producing species specific AI-2. This process of quorum sensing allows LsrB to function as a periplasmic AI-2 binding protein in interspecies signaling.
Jiyao W et al.(2023). "The conserved domain database in 2023.",