Escherichia coli iron enterobactin uptake monitored by Mössbauer spectroscopy.
AUTOR(ES)
Matzanke, B F
RESUMO
Iron uptake by Escherichia coli under aerobic conditions of iron deficiency is mediated by a highly stable ferric enterobactin [Fe(ent)3-] siderophore complex. Mössbauer spectroscopy has been used to monitor the fate of the iron as 57Fe(ent) was taken up by the cells. Osmotic shock experiments were used to distinguish between the iron present in the periplasmic space and that in the cytoplasm of the cell. Iron delivery by a synthetic analog of enterobactin, 1,3,5-N,N',N''- tris-(2,3-dihydroxybenzoyl)triaminomethylbenzene (MECAM), was also studied. Although Fe-MECAM was transported at the same rate as was Fe(ent) across the outer membrane and was apparently accumulated in the periplasmic space, the subsequent behaviors of Fe(ent) and Fe-MECAM were very different. After more than 30 min, a major fraction of the iron originally absorbed as ferric enterobactin appeared as Fe(II), apparently in the cytoplasm of the cell. However, little iron was delivered to the cytoplasm by the MECAM complex. The differences in specificity of these two stages of iron uptake by E. coli are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=212942Documentos Relacionados
- Anaerobic iron uptake by Escherichia coli.
- Quantitative studies of ferritinlike iron in erythrocytes of thalassemia, sickle-cell anemia, and hemoglobin Hammersmith with Mössbauer spectroscopy.
- MÖSSBAUER SPECTROSCOPY OF THE IRON-SULFUR PROTEINS*
- Structural dynamics of human deoxyhemoglobin and hemochrome investigated by nuclear gamma resonance absorption (Mössbauer) spectroscopy.
- Structural fluctuations of myoglobin from normal-modes, Mössbauer, Raman, and absorption spectroscopy.