Structural highlights
Function
[PTGA_ECOLI] The phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS), a major carbohydrate active -transport system, catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. This system is involved in glucose transport. [PTGCB_ECOLI] The phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS), a major carbohydrate active -transport system, catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. This system is involved in glucose transport. This enzyme is also a chemoreceptor monitoring the environment for changes in sugar concentration.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The solution structure of the final phosphoryl transfer complex in the glucose-specific arm of the Escherichia coli phosphotransferase system, between enzyme IIAGlucose (IIAGlc) and the cytoplasmic B domain (IIBGlc) of the glucose transporter IICBGlc, has been solved by NMR. The interface (approximately 1200-A2 buried surface) is formed by the interaction of a concave depression on IIAGlc with a convex protrusion on IIBGlc. The phosphoryl donor and acceptor residues, His-90 of IIAGlc and Cys-35 of IIBGlc (residues of IIBGlc are denoted in italics) are in close proximity and buried at the center of the interface. Cys-35 is primed for nucleophilic attack on the phosphorus atom by stabilization of the thiolate anion (pKa approximately 6.5) through intramolecular hydrogen bonding interactions with several adjacent backbone amide groups. Hydrophobic intermolecular contacts are supplemented by peripheral electrostatic interactions involving an alternating distribution of positively and negatively charged residues on the interaction surfaces of both proteins. Salt bridges between the Asp-38/Asp-94 pair of IIAGlc and the Arg-38/Arg-40 pair of IIBGlc neutralize the accumulation of negative charge in the vicinity of both the Sgamma atom of Cys-35 and the phosphoryl group in the complex. A pentacoordinate phosphoryl transition state is readily accommodated without any change in backbone conformation, and the structure of the complex accounts for the preferred directionality of phosphoryl transfer between IIAGlc and IIBGlc. The structures of IIAGlc.IIBGlc and the two upstream complexes of the glucose phosphotransferase system (EI.HPr and IIAGlc.HPr) reveal a cascade in which highly overlapping binding sites on HPr and IIAGlc recognize structurally diverse proteins.
Solution structure of the phosphoryl transfer complex between the signal-transducing protein IIAGlucose and the cytoplasmic domain of the glucose transporter IICBGlucose of the Escherichia coli glucose phosphotransferase system.,Cai M, Williams DC Jr, Wang G, Lee BR, Peterkofsky A, Clore GM J Biol Chem. 2003 Jul 4;278(27):25191-206. Epub 2003 Apr 25. PMID:12716891[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Cai M, Williams DC Jr, Wang G, Lee BR, Peterkofsky A, Clore GM. Solution structure of the phosphoryl transfer complex between the signal-transducing protein IIAGlucose and the cytoplasmic domain of the glucose transporter IICBGlucose of the Escherichia coli glucose phosphotransferase system. J Biol Chem. 2003 Jul 4;278(27):25191-206. Epub 2003 Apr 25. PMID:12716891 doi:10.1074/jbc.M302677200
