Streptococcus faecalis proton gradients and tetracycline transport.
AUTOR(ES)
Munske, G R
RESUMO
The transport of chlortetracycline by Streptococcus faecalis is energy dependent. Addition of glucose to energy-depleted cells enhances both the transport rates and accumulation levels. Transport rates can be altered independently of glucose by treating cells with ionophores that increase or decrease the proton gradient. The transport of the antibiotic is linked only to the transmembrane pH difference, delta pH, and not the transmembrane electrical potential, delta psi. This conclusion was verified by quantitative measurements of delta pH, delta psi, and tetracycline accumulation levels. A linear correlation between delta pH and the tetracycline electrochemical potential was observed. Tetracycline most likely accumulates by the symport of protons in which the protons are bound to an anionic form of the antibiotic to form an uncharged molecule.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=215377Documentos Relacionados
- Sodium/proton antiporter in Streptococcus faecalis.
- Evidence for rotational contribution to protein-facilitated proton transport.
- Inhibition of Membrane Transport in Streptococcus faecalis by Uncouplers of Oxidative Phosphorylation and Its Relationship to Proton Conduction
- Kinetic analysis of tetracycline accumulation by Streptococcus faecalis.
- Tetracycline resistance element of pBR322 mediates potassium transport.
