文章基本信息

标题：Regulation of Bacterial DNA Packaging in Early Stationary Phase by Competitive DNA Binding of Dps and IHF
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作者：Sin Yi Lee ; Ci Ji Lim ; Peter Dröge 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：5
期号：1
DOI：10.1038/srep18146
语种：English
出版社：Springer Nature
摘要：The bacterial nucleoid, a bacterial genome packed by nucleoid binding proteins, forms the physical basis for cellular processes such as gene transcription and DNA replication. Bacteria need to dynamically modulate their nucleoid structures at different growth phases and in response to environmental changes. At the nutrients deficient stationary phase, DNA-binding proteins from starved cells (Dps) and Integration host factors (IHF) are the two most abundant nucleoid associated proteins in E. coli . Yet, it remains unclear how the nucleoid architecture is controlled by the interplay between these two proteins, as well as the nucleoid’s response to environmental changes. This question is addressed here using single DNA manipulation approach. Our results reveal that the two proteins are differentially selected for DNA binding, which can be tuned by changing environmental factors over physiological ranges including KCl (50–300 mM), MgCl₂ (0–10 mM), pH (6.5–8.5) and temperature (23–37 °C). Increasing pH and MgCl₂ concentrations switch from Dps-binding to IHF-binding. Stable Dps-DNA and IHF-DNA complexes are insensitive to temperature changes for the range tested. The environment dependent selection between IHF and Dps results in different physical organizations of DNA. Overall, our findings provide important insights into E. coli nucleoid architecture.