ALLOSTERIC REGULATION OF THE GLUCOSE-H+ SYMPORTER OF LACTOBACILLUS-BREVIS - COOPERATIVE BINDING OF GLUCOSE AND HPR(SER-P)

Lactobacillus brevis transports glucose and the nonmetabolizable glucose analog 2-deoxyglucose via a proton symport mechanism that is allosterically inhibited by the seryl-phosphorylated derivative of HPr, the small phosphocarrier protein of the phosphotransferase system. We here demonstrate that S46DHPr, a mutant analog of HPr which conformationally resembles HPr(ser-P) but not free HPr, specifically binds to membranes derived from glucose-grown L. brevis cells if and only if a substrate of the glucose permease is also present.