Periplasmic binding protein (LuxP) of autoinducer-2 (AI-2) receptor LuxPQ from Vibrio harveyi and its close homologs
Periplasmic binding protein (LuxP) of autoinducer-2 (AI-2) receptor LuxPQ from Vibrio harveyi and its close homologs from other bacteria. The members of this group are highly homologous to a family of periplasmic pentose/hexose sugar-binding proteins that function as the primary receptors for chemotaxis and transport of many sugar based solutes in bacteria and archaea, and that are members of the type I periplasmic binding protein superfamily. The Vibrio harveyi AI-2 receptor consists of two polypeptides, LuxP and LuxQ: LuxP is a periplasmic binding protein that binds AI-2 by clamping it between two domains, LuxQ is an integral membrane protein belonging to the two-component sensor kinase family. Unlike AI-2 bound to the LsrB receptor in Salmonella typhimurium, the Vibrio harveyi AI-2 signaling molecule 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 LuxPQ to control light production as well as its motility behavior.