scholarly journals Succinate uptake and related proton movements in Escherichia coli K12

1975 ◽  
Vol 152 (3) ◽  
pp. 647-654 ◽  
Author(s):  
S J Gutowski ◽  
H Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Dicarboxylic Acid ◽  
Transport System ◽  
Dicarboxylic Acids ◽  
Acid Transport ◽  
Cationic Form ◽  
Whole Cells ◽  
Escherichia Coli K12 ◽  
Proton Uptake

1. The apparent Km values for succinate uptake by whole cells of Escherichia coli K12 depend on pH in the range 6.5-7.4.2. Uptake of succinate in lightly buffered medium is accompanied by proton uptake. 3. The apparent Km values for succinate uptake and for succinate-induced proton uptake are similar. 4. Approximately two protons enter the cell with each succinate molecule. 5. The pattern of inhibition of succinate uptake is similar to that of succinate-induced proton uptake. 6. Uptake of fumarate and malate, which share the succinate-transport system, is also accompanied by the uptake of approximately two protons per molecule of fumarate or malate. 7. Uptake of aspartate by the dicarboxylic acid-transport system is accompanied by the uptake of approximatley two protons per molecule of asparatate. 8. It is concluded that uptake of dicarboxylic acids by the dicarboxylic acid-transport system is obligatorily coupled to proton uptake such that succinate, malate and fumarate are taken up in electroneutral form and asparate is taken up in cationic form. 9. These results are consistent with, though they do not definitely prove, the energization of succinate uptake of the deltapH.

Dicarboxylic acid transport in Escherichia coli K12: involvement of a binding protein in the translocation of dicarboxylic acids across the outer membrane of the cell envelope

1979 ◽  
Vol 57 (6) ◽  
pp. 653-661 ◽  
Author(s):  
Mary A. Bewick ◽  
Theodore C. Y. Lo
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Outer Membrane ◽  
Transport System ◽  
Cell Envelope ◽  
Binding Protein ◽  
Dicarboxylic Acids ◽  
Escherichia Coli K12 ◽  
Dicarboxylate Transport ◽  
Active Transport System

We have previously found that the dicarboxylate transport system in Escherichia coli K12 is an active transport system and that at least one binding protein and two cytoplasmic membrane transport components are involved in the uptake of dicarboxylic acids. Recently, through surface labelling studies, some dicarboxylate binding proteins were found to be exposed on the cell surface. In the present paper, we demonstrate that the dicarboxylate transport component located in the outer membrane can be inactivated by two different kinds of nonpenetrating inhibitors, viz. proteases, and diazosulfanilic acid. These inhibitors seem to act on the dicarboxylate binding protein. By adding this protein to inactivated cells or to transport-negative mutants, we have succeeded in reconstituting the dicarboxylate transport system. These findings suggest that the dicarboxylate binding protein found on the cell surface plays an essential role in the translocation of dicarboxylic acids across the outer membrane.

scholarly journals New Substrates for the Dicarboxylate Transport System of Sinorhizobium meliloti

2000 ◽  
Vol 182 (15) ◽  
pp. 4216-4221 ◽  
Author(s):  
Svetlana Yurgel ◽  
Michael W. Mortimer ◽  
Kimberly N. Rogers ◽  
Michael L. Kahn
Keyword(s):  
Dicarboxylic Acid ◽  
Transport System ◽  
Sinorhizobium Meliloti ◽  
Monocarboxylic Acid ◽  
Dicarboxylic Acids ◽  
Carbonyl Groups ◽  
Nitrogen Fixing ◽  
Extended Conformation ◽  
Dicarboxylate Transport ◽  
Succinamic Acid

ABSTRACT The dicarboxylate transport (Dct) system of Sinorhizobium meliloti, which is essential for a functional nitrogen-fixing symbiosis, has been thought to transport only dicarboxylic acids. We show here that the permease component of the Dct system, DctA, can transport orotate, a monocarboxylic acid, with an apparentKm of 1.7 mM and a V maxof 163 nmol min−1 per mg of protein in induced cells. DctA was not induced by the presence of orotate. The transport of orotate was inhibited by several compounds, including succinamic acid and succinamide, which are not dicarboxylic acids. The dicarboxylic acid maleate (cis-butenedioic acid) was not an inhibitor of orotate transport, which suggests that it was not recognized by DctA. However, maleate was an excellent inducer of DctA expression. Our evaluation of 17 compounds as inducers and inhibitors of transport suggests that substrates recognized by S. meliloti DctA must have appropriately spaced carbonyl groups and an extended conformation, while good inducers are more likely to have a curved conformation.

scholarly journals 2-Deoxy-d-galactose, a substrate for the galactose-transport system of Escherichia coli

1977 ◽  
Vol 168 (1) ◽  
pp. 15-22 ◽  
Author(s):  
P J F Henderson ◽  
R A Giddens
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Transport Systems ◽  
Mutual Inhibition ◽  
E Coli ◽  
System 2 ◽  
Galactose Transport ◽  
Proton Uptake ◽  
Inhibition Studies ◽  
Lactose Transport

The following observations showed that 2-deoxy-D-galactose is a useful tool for the isolation and elucidation of the activity of one system for galactose uptake into Escherichia coli. 1. 2-Deoxygalactose, which is not a substrate for growth of E. coli, was transported into strains of the organism induced for galactose transport. 2. By using appropriate mutants it was shown that 2-deoxygalactose is a much better substrate for the galactose-transport system than for the methyl galactoside-transport system. This was confirmed by the results of mutual inhibition studies with substrates of each transport system. 3. The glucose-, arabinose- or lactose-transport systems did not effect significant transport of 2-deoxygalactose. 4. Like other substrates of the galactose-transport system, 2-deoxygalactose promoted effective proton uptake into de-energized suspensions of appropriate E. coli strains. 5. The S183 series of E. coli mutants were found to contain a constitutive galactose-transport system, if 2-deoxygalactose transport is used as one criterion for such activity.

scholarly journals Transport of galactose, glucose and their molecular analogues by Escherichia coli K12

1977 ◽  
Vol 162 (2) ◽  
pp. 309-320 ◽  
Author(s):  
P J F Henderson ◽  
R A Giddens ◽  
M C Jones-Mortimer
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Proton Transport ◽  
Regulatory Mechanism ◽  
Transport Systems ◽  
British Library ◽  
Transport Activity ◽  
Phosphotransferase System ◽  
Escherichia Coli K12 ◽  
Specific Transport System

1. Strains of Escherichia coli K12 were made that are unable to assimilate glucose by the phosphotransferase system, since they lack the glucose-specific components specified by the genes ptsG and ptsM. 2. Derivative organisms lacking the methyl galactoside or galactose-specific transport system were examined for their ability to transport galactose, d-fucose, methyl beta-D-galactoside, glucose, 2-deoxy-D-glucose and methyl alpha-D-glucoside. 3. Galactose, glucose and to a lesser extent fucose are substrates for both transport systems. 4. 2-Deoxyglucose is transported on the galactose-specific but not the methyl galactoside system. 5. The ability of sugars to elicit anaerobic proton transport is associated with the galactose-specific, but not with the methyl galactoside transport activity. Hence a chemiosmotic mechanism of energization is likely to apply to the former but not to the latter. Alternatively the methyl galactoside system may be switched off under certain conditions, which would indicate a novel regulatory mechanism. 6. Details of the procedure for the derivation of strains may be obtained from the authors, and have been deposited as Supplementary Publication SUP 50074 (8 pages at the) British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977), 161,1.

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