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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6
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pubmed:dateCreated |
1992-3-24
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pubmed:abstractText |
The glucose transporter of the bacterial phosphotransferase system couples translocation with phosphorylation of the substrate in a 1:1 stoichiometry. It is a complex consisting of a transmembrane subunit (IIGlc) and a hydrophilic subunit (IIIGlc). Both subunits are transiently phosphorylated. IIIGlc is phosphorylated at a histidyl residue by the cytoplasmic phosphoryl carrier protein phospho-heat-stable phosphoryl carrier protein; IIGlc is phosphorylated at a cysteinyl residue by phospho-IIIGlc. The IIGlc subunit consists of two domains. The N-terminal hydrophobic domain is presumed to span the membrane several times; the C-terminal cytoplasmic domain includes the phosphorylation site. IIGlc phosphorylates glucose and methyl-alpha-D-glucopyranoside in transit across the inner membrane but can also phosphorylate intracellular glucose. Ten mutants resistant against extracellular toxic methyl-alpha-D-glucopyranoside yet capable of phosphorylating intracellular glucose were isolated. Strong impairment of transport activity in these mutants was accompanied by only a slight decrease of phosphorylation activity. Amino acid substitutions occurred at six sites that are clustered in three presumably hydrophilic loops in the transmembrane domain of IIGlc: M17T, M17I, G149S, K150E, S157F, H339Y, and D343G. We presume that the three polypeptide segments are directly involved in sugar translocation and/or binding but are of little importance for phosphorylation activity, folding, and membrane localization of IIGlc.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/DNA, Bacterial,
http://linkedlifedata.com/resource/pubmed/chemical/Glucose,
http://linkedlifedata.com/resource/pubmed/chemical/Methylglucosides,
http://linkedlifedata.com/resource/pubmed/chemical/Monosaccharide Transport Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphotransferases
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
267
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pubmed:geneSymbol |
ptsG
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
3847-51
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:1310984-Amino Acid Sequence,
pubmed-meshheading:1310984-DNA, Bacterial,
pubmed-meshheading:1310984-Escherichia coli,
pubmed-meshheading:1310984-Glucose,
pubmed-meshheading:1310984-Methylglucosides,
pubmed-meshheading:1310984-Molecular Sequence Data,
pubmed-meshheading:1310984-Monosaccharide Transport Proteins,
pubmed-meshheading:1310984-Mutation,
pubmed-meshheading:1310984-Phosphorylation,
pubmed-meshheading:1310984-Phosphotransferases,
pubmed-meshheading:1310984-Plasmids,
pubmed-meshheading:1310984-Sequence Homology, Nucleic Acid
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pubmed:year |
1992
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pubmed:articleTitle |
The glucose transporter of Escherichia coli. Mutants with impaired translocation activity that retain phosphorylation activity.
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pubmed:affiliation |
Department of Biology, Philipps University, Marburg, Germany.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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