Part of the ABC transporter complex LsrABCD involved in autoinducer 2 (AI-2) import. Responsible for energy coupling to the transport system. ATP + H2O + (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran-[AI-2-binding protein]Side 1 = ADP + phosphate + (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuranSide 2 + [AI-2-binding protein]Side 1. The complex is composed of two ATP-binding proteins (LsrA), two transmembrane proteins (LsrC and LsrD) and a solute-binding protein (LsrB). In the absence of AI-2, repressed by LsrR. Induced by AI-2, via release of the LsrR repressor. In the absence of glucose, induced by cAMP-CRP by direct binding to the upstream region of the lsr promoter. Serina et al. reported that the transposon insertion mutant is unable to grow in rich medium at optimal temperature (37 degrees Celsius), whereas it can grow in minimal medium at 37 degrees Celsius and in LD broth at 15 degrees Celsius (PubMed:15380559). In contrast, other studies showed that the gene is not essential for growth in Luria broth (LB) medium at 37 degrees Celsius (PubMed:16738554, PubMed:29463657). Belongs to the ABC transporter superfamily. AI-2 autoinducer porter (TC 3.A.1.2.8) family.