期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 108, 期 12, 页码 5045-5050出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1017744108
关键词
ferric uptake regulator; graded transcription regulation; regulatory metal
资金
- National Research Laboratory of Molecular Microbiology [NRF-2009-0079278]
- Marine and Extreme Genome Research Center
- Ministry of Land, Transport, and Maritime Affairs
- National Research Foundation of Korea [2009-0084757]
- Seoul National University
- Korea Institute of Marine Science & Technology Promotion (KIMST) [20090213, 20046001] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
- National Research Foundation of Korea [2009-0079278, 2009-0084757] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Zinc is one of the essential transition metals in cells. Excess or lack of zinc is detrimental, and cells exploit highly sensitive zinc-binding regulators to achieve homeostasis. In this article, we present a crystal structure of active Zur from Streptomyces coelicolor with three zinc-binding sites (C-, M-, and D-sites). Mutations of the three sites differentially affected sporulation and transcription of target genes, such that C-and M-site mutations inhibited sporulation and derepressed all target genes examined, whereas D-site mutations did not affect sporulation and derepressed only a sensitive gene. Biochemical and spectroscopic analyses of representative metal site mutants revealed that the C-site serves a structural role, whereas the M-and D-sites regulate DNA-binding activity as an on-off switch and a fine-tuner, respectively. Consistent with differential effect of mutations on target genes, zinc chelation by TPEN derepressed some genes (znuA, rpmF2) more sensitively than others (rpmG2, SCO7682) in vivo. Similar pattern of TPEN-sensitivity was observed for Zur-DNA complexes formed on different promoters in vitro. The sensitive promoters bound Zur with lower affinity than the less sensitive ones. EDTA-treated apo-Zur gained its DNA binding activity at different concentrations of added zinc for the two promoter groups, corresponding to free zinc concentrations of 4.5 x 10(-16) M and 7.9 x 10(-16) M for the less sensitive and sensitive promoters, respectively. The graded expression of target genes is a clever outcome of subtly modulating Zur-DNA binding affinities in response to zinc availability. It enables bacteria to detect metal depletion with improved sensitivity and optimize gene-expression pattern.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据