3mwm | pdb_00003mwm

Graded expression of zinc-responsive genes through two regulatory zinc-binding sites in Zur

spinqualitylabelsall models 3mwm, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3mwm is a 2 chain structure with sequence from "actinomyces_coelicolor"_(muller_1908)_lieske_1921 "actinomyces coelicolor" (muller 1908) lieske 1921. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ZN Gene: zur gene ("Actinomyces coelicolor" (Muller 1908) Lieske 1921) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed 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 4.5x10(-16) M and 7.9x10(-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. Graded expression of zinc-responsive genes through two regulatory zinc-binding sites in Zur.,Shin JH, Jung HJ, An YJ, Cho YB, Cha SS, Roe JH Proc Natl Acad Sci U S A. 2011 Mar 22;108(12):5045-50. Epub 2011 Mar 7. PMID:21383173 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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