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Acta Physiologica Scandinavica.... Aug 1998
Review
Topics: Amino Acid Sequence; Carrier Proteins; Energy Metabolism; Escherichia coli; Escherichia coli Proteins; Membrane Transport Proteins; Molecular Conformation; Molecular Sequence Data; Monosaccharide Transport Proteins; Structure-Activity Relationship; Symporters
PubMed: 9789544
DOI: No ID Found -
Annals of the New York Academy of... 1985
Review
Topics: Amino Acid Sequence; Antibodies, Monoclonal; Binding Sites; Biological Transport, Active; Cell Membrane; Cell Membrane Permeability; Electrochemistry; Electron Transport Complex IV; Escherichia coli; Escherichia coli Proteins; Freeze Fracturing; Galactosides; Hydrogen-Ion Concentration; Immunologic Techniques; Kinetics; Lactose; Liposomes; Macromolecular Substances; Membrane Transport Proteins; Microscopy, Electron; Molecular Weight; Monosaccharide Transport Proteins; Mutation; Osmosis; Protein Conformation; Protons; Structure-Activity Relationship; Symporters
PubMed: 3004294
DOI: 10.1111/j.1749-6632.1985.tb14879.x -
Biochimica Et Biophysica Acta Jul 1990Different classes of apparently unrelated permeases couple different forms of energy to solute transport. While the energy coupling mechanisms utilized by the different... (Review)
Review
Different classes of apparently unrelated permeases couple different forms of energy to solute transport. While the energy coupling mechanisms utilized by the different permease classes are clearly distinct, it is proposed, based on structural comparisons, that many of these permeases possess transmembrane, hydrophobic domains which are evolutionarily related. Carriers may have arisen from transmembrane pore-forming proteins, and the protein constituents or domains which are specifically responsible for energy coupling may have had distinct origins. Thus, complex permeases may possess mosaic structures. This suggestion is substantiated by recent findings regarding the evolutionary origins of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS). Mechanistic implications of this proposal are presented.
Topics: Biological Evolution; Escherichia coli; Membrane Transport Proteins; Phosphotransferases
PubMed: 2168212
DOI: 10.1016/0005-2728(90)90259-7 -
Society of General Physiologists Series 1993
Review
Topics: Amino Acid Sequence; Escherichia coli; Escherichia coli Proteins; Membrane Proteins; Membrane Transport Proteins; Molecular Sequence Data; Monosaccharide Transport Proteins; Symporters
PubMed: 8503038
DOI: No ID Found -
FEBS Letters Aug 1988The integral membrane protein lactose permease of Escherichia coli was purified to homogeneity in detergent micelles. No other proteins could be detected in the final...
The integral membrane protein lactose permease of Escherichia coli was purified to homogeneity in detergent micelles. No other proteins could be detected in the final product. The molar ratio of lactose permease to lipid was less than 0.2 in detergent solution, thus the preparation was essentially lipid-free. All molecules were functionally active as shown by substrate binding.
Topics: Cell Membrane; Chromatography, Ion Exchange; Dimyristoylphosphatidylcholine; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Escherichia coli Proteins; Membrane Transport Proteins; Monosaccharide Transport Proteins; Phosphatidylethanolamines; Symporters
PubMed: 3042460
DOI: 10.1016/0014-5793(88)81229-8 -
The Journal of Biological Chemistry Jan 2012Resistance to arsenite (As(III)) by cells is generally accomplished by arsenite efflux permeases from Acr3 or ArsB unrelated families. We analyzed the function of three...
Resistance to arsenite (As(III)) by cells is generally accomplished by arsenite efflux permeases from Acr3 or ArsB unrelated families. We analyzed the function of three Acr3 proteins from Corynebacterium glutamicum, CgAcr3-1, CgAcr3-2, and CgAcr3-3. CgAcr3-1 conferred the highest level of As(III) resistance and accumulation in vivo. CgAcr3-1 was also the most active when everted membranes vesicles from Escherichia coli or C. glutamicum mutants were assayed for efflux with different energy sources. As(III) and antimonite (Sb(III)) resistance and accumulation studies using E. coli or C. glutamicum arsenite permease mutants clearly show that CgAcr3-1 is specific for As(III). In everted membrane vesicles expressing CgAcr3-1, dissipation of either the membrane potential or the pH gradient of the proton motive force did not prevent As(III) uptake, whereas dissipation of both components eliminated uptake. Further, a mutagenesis study of CgAcr3-1 suggested that a conserved cysteine and glutamate are involved in active transport. Therefore, we propose that CgAcr3-1 is an antiporter that catalyzes arsenite-proton exchange with residues Cys129 and Glu305 involved in efflux.
Topics: Amino Acid Sequence; Antiporters; Arsenites; Bacterial Proteins; Biocatalysis; Biological Transport; Cell Membrane; Corynebacterium glutamicum; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Membrane Potentials; Membrane Transport Proteins; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Structure, Tertiary; Protons; Sequence Homology, Amino Acid; Substrate Specificity
PubMed: 22102279
DOI: 10.1074/jbc.M111.263335 -
Proceedings of the National Academy of... Jul 1990The membrane topology of Escherichia coli lac permease was analyzed using a set of 36 lac permease-alkaline phosphatase (lacY-phoA) gene fusions. The level of enzymatic...
The membrane topology of Escherichia coli lac permease was analyzed using a set of 36 lac permease-alkaline phosphatase (lacY-phoA) gene fusions. The level of enzymatic activity of alkaline phosphatase fused to a cytoplasmic membrane protein appears to reflect whether the fusion junction site normally faces the cytoplasm or periplasm. The alkaline phosphatase activities of cells expressing the lacY-phoA fusions distinguish between models previously proposed for the topology of lac permease and favor one with 12 transmembrane segments. This model is fully compatible with the results of earlier biochemical and immunological studies. The properties of fusions with junctions spanning two of the transmembrane segments at 2- or 3-amino acid intervals indicate that approximately half of the residues of either segment (9-11 amino acids) suffices to promote alkaline phosphatase translocation across the membrane. The additional transmembrane segment amino acids that are not required for this membrane insertion process may normally be needed in unfused lac permease after insertion for stable association with the membrane.
Topics: Alkaline Phosphatase; Amino Acid Sequence; Cell Membrane; Cloning, Molecular; DNA Transposable Elements; Escherichia coli; Escherichia coli Proteins; Gene Expression; Genes, Bacterial; Membrane Transport Proteins; Models, Structural; Molecular Sequence Data; Monosaccharide Transport Proteins; Plasmids; Protein Conformation; Recombinant Fusion Proteins; Restriction Mapping; Symporters
PubMed: 2164211
DOI: 10.1073/pnas.87.13.4937 -
Hoppe-Seyler's Zeitschrift Fur... Dec 1982
Topics: Amino Acid Sequence; Biological Transport, Active; Escherichia coli; Escherichia coli Proteins; Kinetics; Membrane Transport Proteins; Models, Biological; Molecular Biology; Molecular Weight; Monosaccharide Transport Proteins; Protein Binding; Protein Conformation; Symporters; Thermodynamics
PubMed: 6761260
DOI: 10.1515/bchm2.1982.363.2.1409 -
Annals of the New York Academy of... 1985
Review
Topics: Affinity Labels; Amino Acid Sequence; Base Sequence; Binding Sites; Cell Membrane; Cysteine; Cytoplasm; DNA, Bacterial; Escherichia coli; Escherichia coli Proteins; Ethylmaleimide; Immunologic Techniques; Iodine Radioisotopes; Membrane Transport Modulators; Membrane Transport Proteins; Molecular Weight; Monosaccharide Transport Proteins; Mutation; Peptide Fragments; Protein Conformation; Symporters; Thermolysin
PubMed: 3911841
DOI: 10.1111/j.1749-6632.1985.tb14882.x -
Biochemistry Jun 1992Previous studies utilizing site-directed mutagenesis [Pourcher et al. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 468-472] indicate that out of seven histidinyl residues in...
Previous studies utilizing site-directed mutagenesis [Pourcher et al. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 468-472] indicate that out of seven histidinyl residues in the melibiose (mel) permease of Escherichia coli, only His94 is important. The role of His94 has now been investigated by replacing the residue with Asn, Gln, or Arg. Cells expressing mel permease with Asn94 or Gln94 retain 30% or 20% of wild-type activity, respectively, and surprisingly, immunological assays demonstrate that diminished transport activity is due to a proportional reduction in the amount of permease in the membrane. Moreover, kinetic analyses of transport and ligand binding studies with right-side-out membrane vesicles indicate that both substrate recognition and turnover (kcat) are comparable in the mutant permeases and the wild-type. Mel permease with Arg in place of His94 also binds ligand and catalyzes sugar accumulation, but only when the cells are grown at 30 degrees C, and evidence is presented that Arg94 permease is inactivated at 37 degrees C. Finally, labeling studies demonstrate that expression and/or insertion of the permease, but not degradation, is strongly dependent on the amino acid present at position 94 and temperature. The findings indicate that an imidazole group at position 94 is required for proper insertion and stability of mel permease, but not for transport activity per se. Since replacement of the other six histidinyl residues in mel permease with Arg has little or no effect on transport activity, it is concluded that histidinyl residues do not play a direct role in the mechanism of this secondary transport protein.
Topics: Base Sequence; Biological Transport; Blotting, Western; Catalysis; Cations; Enzyme Stability; Escherichia coli; Gene Expression; Histidine; Kinetics; Melibiose; Membrane Transport Proteins; Methionine; Methylgalactosides; Molecular Sequence Data; Mutagenesis, Site-Directed; Plasmids; Symporters; Temperature; Thiogalactosides
PubMed: 1606146
DOI: 10.1021/bi00137a018