1pdo
PHOSPHOENOLPYRUVATE-DEPENDENT PHOSPHOTRANSFERASE SYSTEMPHOSPHOENOLPYRUVATE-DEPENDENT PHOSPHOTRANSFERASE SYSTEM
Structural highlights
Function[PTNAB_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 mannose transport. 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 PubMedThe mannose transporter from Escherichia coli is a member of the phosphoenolpyruvate-dependent phosphotransferase system. The multi-subunit complex couples translocation across the bacterial inner membrane with phosphorylation of the solute. A functional fragment (IIA(Man), residues 2 to 133) of the membrane-associated IIAB(Man) subunit of the mannose transporter was expressed as a selenomethionine protein, and the unphosphorylated molecule was crystallized and its structure solved by X-ray crystallography. The protein consists of a central five-stranded beta-sheet covered by helices on either face. The order of the secondary structure elements is (beta alpha)4, alpha beta. Four beta-strands are arranged in a parallel manner with strand order 2134 and are linked by helices forming right-handed cross-over connections. The fifth strand that forms one edge of the sheet and runs antiparallel to the others is swapped between the subunits of the dimeric structure. Helices D and E form a helical hairpin. Histidine 10, which is transiently phosphorylated during catalysis, is located at the topological switch-point of the structure, close to the subunit interface. Its imidazole ring is hydrogen bonded to the buried side-chain of Asp67. It is likely that Asp67 acts as a general base and thus increases the nucleophilicity of the histidine. Modeling suggests that the covalently bound phosphoryl group would be stabilized by the macrodipole of helix C. Putative interactions between IIA(Man) and the histidine-containing phosphocarrier protein are discussed. Structure of the IIA domain of the mannose transporter from Escherichia coli at 1.7 angstroms resolution.,Nunn RS, Markovic-Housley Z, Genovesio-Taverne JC, Flukiger K, Rizkallah PJ, Jansonius JN, Schirmer T, Erni B J Mol Biol. 1996 Jun 14;259(3):502-11. PMID:8676384[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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