REGULATION OF GLYCEROL AND MALTOSE UPTAKE BY THE IIA(GLC)-LIKE DOMAINOF II(NAG) OF THE PHOSPHOTRANSFERASE SYSTEM IN SALMONELLA-TYPHIMURIUMLT2

In Enterobacteriaceae the nonphosphorylated form of IIA(Glc) of the ph osphoenolpyruvate-dependent phosphotransferase system (PTS) can inhibi t the uptake and subsequent metabolism of glycerol and maltose by bind ing to, and inhibiting, glycerol kinase and the MalK protein of the ma ltose transport system, respectively. In this report we show that the IIA(Glc)-like domain of the membrane-bound IIN-acetylglucosamine (IINa g) of the PTS can replace IIA(Glc) in a Salmonella typhimurium crr mut ant strain that lacks all soluble IIA(Glc). The inhibition was most se vere in cells which were partially induced for the glycerol or maltose uptake systems. The Streptococcus thermophilus lactose transporter La cS, which also contains a IIA(Glc)-like domain, could not replace IIA( Glc). Neither IINag nor LacS could replace IIA(Glc) in activation of a denylate cyclase.