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Energetics of alanine, lysine, and proline transport in cytoplasmic membranes of the polyphosphate-accumulating Acinetobacter johnsonii strain 210A
- Source :
- Journal of Bacteriology 176 (1994), Journal of Bacteriology, 176, 2670-2676, Journal of Bacteriology, 176(9), 2670-2676. AMER SOC MICROBIOLOGY
- Publication Year :
- 1994
- Publisher :
- AMER SOC MICROBIOLOGY, 1994.
-
Abstract
- Amino acid transport in right-side-out membrane vesicles of Acinetobacter johnsonii 210A was studied. L-Alanine, L-lysine, and L-proline were actively transported when a proton motive force of -76 mV was generated by the oxidation of glucose via the membrane-bound glucose dehydrogenase. Kinetic analysis of amino acid uptake at concentrations of up to 80 microM revealed the presence of a single transport system for each of these amino acids with a Kt of less than 4 microM. The mode of energy coupling to solute uptake was analyzed by imposition of artificial ion diffusion gradients. The uptake of alanine and lysine was driven by a membrane potential and a transmembrane pH gradient. In contrast, the uptake of proline was driven by a membrane potential and a transmembrane chemical gradient of sodium ions. The mechanistic stoichiometry for the solute and the coupling ion was close to unity for all three amino acids. The Na+ dependence of the proline carrier was studied in greater detail. Membrane potential-driven uptake of proline was stimulated by Na+, with a half-maximal Na+ concentration of 26 microM. At Na+ concentrations above 250 microM, proline uptake was strongly inhibited. Generation of a sodium motive force and maintenance of a low internal Na+ concentration are most likely mediated by a sodium/proton antiporter, the presence of which was suggested by the Na(+)-dependent alkalinization of the intravesicular pH in inside-out membrane vesicles. The results show that both H+ and Na+ can function as coupling ions in amino acid transport in Acinetobacter spp.
- Subjects :
- Proline
PH
Antiporter
Sodium
Glucose Dehydrogenases
BACTERIAL-CELLS
chemistry.chemical_element
Biology
Microbiology
Membrane Potentials
VESICLES
DEHYDROGENASE
Polyphosphates
Microbiologie
Glucose dehydrogenase
Proline transport
Food Chemistry and Microbiology
Life Science
Electrochemical gradient
LACTOCOCCUS-LACTIS
Molecular Biology
VLAG
Alanine
chemistry.chemical_classification
Membranes
Acinetobacter
Lysine
SALMONELLA-TYPHIMURIUM
Biological Transport
Glucose 1-Dehydrogenase
Membrane transport
STREPTOCOCCUS-CREMORIS
Amino acid
Kinetics
Glucose
RECONSTITUTION
Levensmiddelenchemie en -microbiologie
chemistry
Biochemistry
ESCHERICHIA-COLI
Biophysics
AMINO-ACID-TRANSPORT
Protons
Carrier Proteins
Energy Metabolism
Research Article
Subjects
Details
- Language :
- English
- ISSN :
- 00219193
- Volume :
- 176
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- Journal of Bacteriology
- Accession number :
- edsair.doi.dedup.....3f084f0042fdd0beccb6287449d76073