Glutamate transport driven by an electrochemical gradient of sodium ions in Escherichia coli.
AUTOR(ES)
Tsuchiya, T
RESUMO
The role of Na+ in glutamate transport was studied in Escherichia coli B, strain 29-78, which possesses a very high activity of glutamate transport (L. Frank and I. Hopkins, J. Bacteriol., 1969). Energy-depleted cells were exposed to radioactive glutamate in the presence of a sodium gradient, a membrane potential, or both. One hundred- to 200-fold accumulation of the amino acid was attained in the presence of both electrical and chemical driving forces for the sodium ion. Somewhat lower accumulation values were obtained when either chemical or electrical driving forces were applied separately. A chemical driving force was produced by the addition of external Na+ to Na+-free cells. A membrane potential was established by a diffusion potential either of H+ in the presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone or of SCN-. These results support the hypothesis of a Na+-glutamate cotransport. Na+-driven glutamate transport was also observed in wild-type E. coli B but not in a strain of K-12.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=235540Documentos Relacionados
- Amino acid transport in the thermophilic anaerobe Clostridium fervidus is driven by an electrochemical sodium gradient.
- Sodium-Stimulated Transport of Glutamate in Escherichia coli
- Role of lithium ions in proline transport in Escherichia coli.
- Identification of the structural proteins of an ATP-driven potassium transport system in Escherichia coli.
- Effect of silver ions on transport and retention of phosphate by Escherichia coli.
