Molecular Insights into the Metal Selectivity of the Copper(I)-Sensing Repressor CsoR from <i>Bacillus subtilis</i>

Ma, Zhen; Cowart, Darin M.; Scott, Robert A.; Giedroc, David P.

doi:10.1021/bi900115w

Cited by 102 publications

(179 citation statements)

References 34 publications

(90 reference statements)

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“…As shown in Fig. 2A, the preedge peak of Cu(I)-CsoR at 8940 eV is consistent with a 1s 3 4p excitation typical for 3-coordinate Cu(I) (13,15,26). The copper K-edge EXAFS spectrum as well as its Fourier transform for Sau CsoR with the best fit are shown in Fig.…”

Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinsupporting

confidence: 71%

“…S3, inset). Similar features characterize Cu(I) binding to Mtb and Bsu CsoRs (13,15,16). The Cu(I) binding affinity (K Cu ) was further quantified using an anaerobic bathocuprione disulfonate competition assay with log K Cu determined to be 18.1 Ϯ 0.5 (supplemental Table S1).…”

Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinmentioning

confidence: 99%

“…XAS data were collected at Stanford Synchrotron Radiation Lightsource (SSRL) on beamline 9-3. Extended x-ray absorption fine structure (EXAFS) data analysis was performed using EXAFSPAK software, using ab initio phase and amplitude functions computed with FEFF version 7.2, according to standard procedures as described (15,16,21).…”

Section: Bacterial Expression Plasmid Construction and Csor Purificatmentioning

confidence: 99%

“…The significant outer shell scattering at 3-4 Å suggests that the third ligand is a histidine residue. Sau CsoR His 66 corresponds to His 61 in Mtb CsoR and His 70 in Bsu CsoR (13,15) and the Cu(I) binding affinity is significantly decreased in the H66A mutant (supplemental Table S1). These data reveal that His 66 is a Cu(I) ligand that together with Cys 41 and Cys 70 complete the S 2 N coordination complex.…”

Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinmentioning

confidence: 99%

“…Two cysteine residues on opposite subunits within a dimer make coordination bonds to the Cu(I) ion, with the third ligand a His from the ␣2 helix (Cys 36 Ј, His 61 , Cys 65 ), thus completing a trigonal S 2 N coordination complex (13). Additionally, two conserved second coordination shell residues, Tyr 35 Ј and Glu 81 , play critical roles in driving allosteric negative regulation of DNA binding by Cu(I) within the tetramer (15,16).…”

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confidence: 99%

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Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Grossoehme

Kehl-Fie

et al. 2011

Journal of Biological Chemistry

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214

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All strains of Staphylococcus aureus encode a putative copper-sensitive operon repressor (CsoR) and one other CsoR-like protein of unknown function. We show here that NWMN_1991 encodes a bona fide Cu(I)-inducible CsoR of a genetically unlinked copA-copZ copper resistance operon in S. aureus strain Newman. In contrast, an unannotated open reading frame found between NWMN_0027 and NWMN_0026 (denoted NWMN_0026.5) encodes a CsoR-like regulator that represses expression of adjacent genes by binding specifically to a pair of canonical operator sites positioned in the NWMN_0027-0026.5 intergenic region. Inspection of these regulated genes suggests a role in assimilation of inorganic sulfur from thiosulfate and vectorial sulfur transfer, and we designate NWMN_ 0026.5 as CstR (CsoR-like sulfur transferase repressor). Expression analysis demonstrates that CsoR and CstR control their respective regulons in response to distinct stimuli with no overlap in vivo. Unlike CsoR, CstR does not form a stable complex with Cu(I); operator binding is instead inhibited by oxidation of the intersubunit cysteine pair to a mixture of disulfide and trisulfide linkages by a likely metabolite of thiosulfate assimilation, sulfite. CsoR is unreactive toward sulfite under the same conditions. We conclude that CsoR and CstR are paralogs in S. aureus that function in the same cytoplasm to control distinct physiological processes.The Gram-positive opportunistic human pathogen Staphylococcus aureus is the causative agent of a wide range of hospital and community-acquired infections that are associated with significant morbidity (1). With the incidence of methicillinresistant strains increasing in previously low prevalence areas (2), new antibiotic therapies that target novel metabolic pathways are urgently needed. One approach is to target those processes that allow a pathogen to respond to environmental stresses that might change depending on the microenvironmental host niche in which the organism finds itself. Resistance to host-mediated copper killing of Escherichia coli (3), Salmonella enterica (4), and Mycobacterium tuberculosis (5, 6) and sulfur assimilation and cysteine biosynthesis in M. tuberculosis (7,8) are two such processes. S. aureus is particularly sensitive to rapid killing when exposed to copper or copper alloy surfaces, justifying this therapeutic direction (9, 10).M. tuberculosis CsoR 6 (copper-sensitive operon repressor) is a founding member of large family of regulators now known collectively to respond to Cu(I), Ni(II), and perhaps other stressors, the structural basis of which is not fully understood (11, 12). All CsoR family proteins lack a known canonical DNA binding domain and are projected to adopt the flat disc-shaped dimer of dimers homotetrameric structure characteristic of Cu(I)-sensing CsoRs, with individual dimers consisting of an antiparallel four-helix bundle flanked by a C-terminal ␣3 helix (13,14). Two cysteine residues on opposite subunits within a dimer make coordination bonds to the Cu(I) ion, with the third ...

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Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinsupporting

confidence: 71%

Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinmentioning

confidence: 99%

Section: Bacterial Expression Plasmid Construction and Csor Purificatmentioning

confidence: 99%

Section: Sau Csor Binds 1 Mol Eq Of Cu(i) Per Monomer With High Affinmentioning

confidence: 99%

mentioning

confidence: 99%

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Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Grossoehme

Kehl-Fie

et al. 2011

Journal of Biological Chemistry

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214

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Metal Specificity of Metallosensors

Higgins

Giedroc

2004

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Transition metal ions are biologically required yet toxic when in excess. As such, prokaryotes have developed metal homeostasis systems that allow for the acquisition of essential metal ions, the delivery of these metal ions to target proteins, and the export of metal ions from the cell. Specialized metal‐binding proteins termed metallosensors bind to a cognate metal ion(s) in the cell and either transcriptionally repress the expression of importers or de‐repress the expression of exporters or sequestration systems and therefore govern cellular metal homeostasis. Metallosensors must be selective and appropriately sensitive toward the binding of their cognate metals. Prokaryotic metallosensors have been identified in ten different protein structural families. Each family exploits either one general metal‐binding‐site region, individual members of which have evolved different coordination sites, or alternatively, employs multiple metal‐binding sites to effect coordination of different metal ions. There is now broad support for the hypothesis that metal responsiveness in metallosensors is most closely linked to the coordination number and geometry adopted by cognate metal ion(s), and this is the subject of this article. Since a range of metal ions can be collectively sensed by a single repressor family, a particular protein fold cannot be specific for one particular metal ion. In fact, the converse is true: nature has used convergent evolution to evolve metal‐specific sensors on a variety of structural scaffolds that exploit common principles of coordination chemistry (ligand type, coordination number, and geometry) to effect the same biological outcome.

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Metal Homeostasis and Oxidative Stress in Bacillus subtilis

Helmann

2004

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Bacteria have evolved mechanisms to maintain proper concentration of different metal ions, a process known as metal ion homeostasis . Metal‐dependent transcription regulators, or metalloregulatory proteins, play major roles in coordinating the expression of metal ion homeostasis genes. Bacillus subtilis has been a model Gram‐positive bacterium for studies of metal ion homeostasis for decades. In this article, we review how B. subtilis senses and responds to metal ion deficiency, sufficiency, and excess. Generally, metal deficiency leads to the expression of high‐affinity metal uptake systems and mobilization of stored metal ions, and may additionally activate elemental sparing responses to minimize metal ion requirements. Excess metal leads to the expression of sequestration or efflux mechanisms. In B. subtilis , these responses are coordinated at the transcription level by metalloregulatory proteins that sense metal ion status. We discuss in detail how each metal ion is sensed by the cognate regulator and how each regulatory circuit achieves a metal‐specific response. Importantly, recent studies suggest an intimate linkage between oxidative stress responses and metal ion homeostasis. In B. subtilis , the peroxide stress regulator (PerR) appears to be a key component linking these two stress responses, as suggested both by the metal‐dependent nature of PerR repression and functions of genes regulated by PerR.

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Molecular Insights into the Metal Selectivity of the Copper(I)-Sensing Repressor CsoR from Bacillus subtilis

Abstract: Bacillus subtilis CsoR (Bsu

Cited by 102 publications

References 34 publications

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Metal Specificity of Metallosensors

Metal Homeostasis and Oxidative Stress in Bacillus subtilis

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