Severe Zinc Depletion of Escherichia coli
| Autor: | Cameron W. McLeod, Sarah L. Stokes, Neil Bramall, Alan G. Cox, Alison I. Graham, Robert K. Poole, Josephine Bunch, Stuart Hunt |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
inorganic chemicals
Growth medium Mutant chemistry.chemical_element Cell Biology Chemostat Zinc Periplasmic space Biology medicine.disease_cause Biochemistry enzymes and coenzymes (carbohydrates) chemistry.chemical_compound chemistry Ribosomal protein biological sciences health occupations medicine bacteria Binding site Molecular Biology Escherichia coli |
| Zdroj: | Journal of Biological Chemistry. 284:18377-18389 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m109.001503 |
| Popis: | Zinc ions play indispensable roles in biological chemistry. However, bacteria have an impressive ability to acquire Zn2+ from the environment, making it exceptionally difficult to achieve Zn2+ deficiency, and so a comprehensive understanding of the importance of Zn2+ has not been attained. Reduction of the Zn2+ content of Escherichia coli growth medium to 60 nm or less is reported here for the first time, without recourse to chelators of poor specificity. Cells grown in Zn2+-deficient medium had a reduced growth rate and contained up to five times less cellular Zn2+. To understand global responses to Zn2+ deficiency, microarray analysis was conducted of cells grown under Zn2+-replete and Zn2+-depleted conditions in chemostat cultures. Nine genes were up-regulated more than 2-fold (p < 0.05) in cells from Zn2+-deficient chemostats, including zinT (yodA). zinT is shown to be regulated by Zur (zinc uptake regulator). A mutant lacking zinT displayed a growth defect and a 3-fold lowered cellular Zn2+ level under Zn2+ limitation. The purified ZinT protein possessed a single, high affinity metal-binding site that can accommodate Zn2+ or Cd2+. A further up-regulated gene, ykgM, is believed to encode a non-Zn2+ finger-containing paralogue of the Zn2+ finger ribosomal protein L31. The gene encoding the periplasmic Zn2+-binding protein znuA showed increased expression. During both batch and chemostat growth, cells “found” more Zn2+ than was originally added to the culture, presumably because of leaching from the culture vessel. Zn2+ elimination is shown to be a more precise method of depleting Zn2+ than by using the chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|