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

Lactobacillus brevis transports glucose and the nonmetabolizable gluco se analog 2-deoxyglucose via a proton symport mechanism that is allost erically 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 conformational ly resembles HPr(ser-P) but not free HPr, specifically binds to membra nes derived from glucose-grown L. brevis cells if and only if a substr ate of the glucose permease is also present.