Functional Characterization and Metal Ion Specificity of the Metal-Citrate Complex Transporter from
            <i>Streptomyces coelicolor</i>

Lensbouer, Joshua J.; Patel, Ami; Sirianni, Joseph P.; Doyle, Robert P.

doi:10.1128/jb.00456-08

Cited by 25 publications

(23 citation statements)

References 26 publications

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“…At that point in time, the concentration of copper in the biofilm was already nearly 14 times higher than that of the medium (2.82 mg g Ϫ1 compared with 0.192 mg g Ϫ1 ). Citrate likely played an important role in the quick penetration of Cu into the biofilm, since metal-citrate transport systems have been identified in many bacteria (21) and P. putida has been found to use metalcitrate complexes as carbon sources (33). The high percentage (52.6 to 61.4%) of citrate-Cu-like species in the biofilm confirms that copper was primarily complexed with citrate in P. putida CZ1 biofilms.…”

Section: Discussionmentioning

confidence: 55%

Sorption and Distribution of Copper in Unsaturated Pseudomonas putida CZ1 Biofilms as Determined by X-Ray Fluorescence Microscopy

Chen

Yang

et al. 2011

Appl Environ Microbiol

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The spatial and temporal distribution of metals in unsaturated Pseudomonas putida CZ1 biofilms was determined using synchrotron-based X-ray fluorescence microscopy (XRF). It was found that Fe, Mn, and Ca were mainly distributed near the air-biofilm interface of a biofilm grown on 40 mM citrate, while there were two Fe-, Mn-, and Ca-rich layers within a biofilm grown on 10 mM citrate. The sorption of copper by biofilm grown in medium containing 10 mM citrate was rapid, with copper being found throughout the biofilm after only 1 h of exposure. Copper initially colocalized with Fe and Mn element layers in the biofilm and then precipitated in a 40-m-thick layer near the air-biofilm interface when exposed for 12 h. Cu K-edge X-ray absorption near edge structure (XANES) analysis revealed that Cu was primarily bound with citrate within the biofilm, and the precipitate formed in the biofilm exposed to copper for 12 h was most similar to copper phosphate. LIVE/DEAD staining revealed that cells at the biofilm-membrane interface were mostly alive even when the copper concentration reached 80.5 mg copper g ؊1 biomass. This suggests that the biofilm matrix provided significant protection for cells in this area. These results significantly improve our understanding of metal acquisition, transportation, and immobilization in unsaturated biofilm systems.

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Section: Discussionmentioning

confidence: 55%

Sorption and Distribution of Copper in Unsaturated Pseudomonas putida CZ1 Biofilms as Determined by X-Ray Fluorescence Microscopy

Chen

Yang

et al. 2011

Appl Environ Microbiol

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“…Given the strong likelihood that any available citrate in the environment of K. radiotolerans would be complexed with metal ions, it seemed likely that any transporters of citrate in K. radiotolerans would be in the form of metal-citrate transporters. We have previously reported on an iron-citrate secondary transporter (Cit Sc ) from the citrate-metal hydrogen symporter (CitMHS) superfamily from Streptomyces coelicolor [7], a distant relative of K. radiotolerans, as noted above. Several reports have also demonstrated that certain bacteria are able to transport citrate complexes (particularly with calcium or magnesium) through CitMHS proteins, including Bacillus subtilis (Cit Bs ) [8], Corynebacterium glutamicum (Cit Cg ) [9], Enterococcus faecalis (Cit Ef ) [10], and Pseudomonas fluorescens (Cit Pf3 ) [11].…”

Section: Introductionmentioning

confidence: 74%

“…Of particular interest was whether copper or manganese played any role, given the findings that copper (Bagwell [3]) and manganese (Ardini [14]) play critical roles in radiation resistance/protection from oxidative stress. The metal-citrate complexes were selected based on prior reports of symport of such (see Table 1 and references [6][7][8][9][10][11][12]). Given the importance of copper to K. radiotolerans resistance mechanism, copper(II) citrate was also included.…”

Section: K Radiotoleransmentioning

confidence: 99%

Metal‐citrate complex transport in Kineococcus radiotolerans

et al. 2017

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The growth of an organism is highly dependent on the acquisition of carbon and metals, and availability of these nutrients in the environment affects its survival. Organisms can obtain both nutrients simultaneously through proteins of the CitMHS superfamily. Bioinformatic studies suggested a CitMHS gene (Accession number ABS03965.1) in Kineococcus radiotolerans. Radio flux assays following 14-C radiolabelled citrate, either free or complexed to a variety of metal ions, in K. radiotolerans demonstrated internalization of the citrate when bound to select metal ions only, primarily in the form of calcium-citrate. A pH response was also observed, consistent with a permease (ATP independent) mechanism as noted for other CitMHS family members, with greater uptake at pH 7 compared to pH 10. These results confirm the ability of K. radiotolerans to transport complexed citrate.

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“…In S. coelicolor, the transport of exogenous citrate across cell membranes is mainly accomplished by the CitMHS family of transporters [24,25]. In S. coelicolor, the transport of exogenous citrate across cell membranes is mainly accomplished by the CitMHS family of transporters [24,25].…”

Section: In Vivo Effect Of Citrate and H 2 O 2 On Transcriptionmentioning

confidence: 99%

The regulatory role of Streptomyces coelicolor TamR in central metabolism

Huang

Sivapragasam

Grove

2015

Biochemical Journal

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Trans-aconitate methyltransferase regulator (TamR) is a member of the ligand-responsive multiple antibiotic resistance regulator (MarR) family of transcription factors. In Streptomyces coelicolor, TamR regulates transcription of tamR (encoding TamR), tam (encoding trans-aconitate methyltransferase) and sacA (encoding aconitase); up-regulation of these genes promotes metabolic flux through the citric acid cycle. DNA binding by TamR is attenuated and transcriptional derepression is achieved on binding of ligands such as citrate and trans-aconitate to TamR. In the present study, we show that three additional genes are regulated by S. coelicolor TamR. Genes encoding malate synthase (aceB1; SCO6243), malate dehydrogenase (mdh; SCO4827) and isocitrate dehydrogenase (idh; SCO7000) are up-regulated in vivo when citrate and trans-aconitate accumulate, and TamR binds the corresponding gene promoters in vitro, a DNA binding that is attenuated by cognate ligands. Mutations to the TamR binding site attenuate DNA binding in vitro and result in constitutive promoter activity in vivo. The predicted TamR binding sites are highly conserved in the promoters of these genes in Streptomyces species that encode divergent tam-tamR gene pairs, suggesting evolutionary conservation. Like aconitase and trans-aconitate methyltransferase, malate dehydrogenase, isocitrate dehydrogenase and malate synthase are closely related to the citric acid cycle, either catalysing individual reaction steps or, in the case of malate synthase, participating in the glyoxylate cycle to produce malate that enters the citric acid cycle to replenish the intermediate pool. Taken together, our data suggest that TamR plays an important and conserved role in promoting metabolic flux through the citric acid cycle.

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Functional Characterization and Metal Ion Specificity of the Metal-Citrate Complex Transporter from Streptomyces coelicolor

Cited by 25 publications

References 26 publications

Sorption and Distribution of Copper in Unsaturated Pseudomonas putida CZ1 Biofilms as Determined by X-Ray Fluorescence Microscopy

Sorption and Distribution of Copper in Unsaturated Pseudomonas putida CZ1 Biofilms as Determined by X-Ray Fluorescence Microscopy

Metal‐citrate complex transport in Kineococcus radiotolerans

The regulatory role of Streptomyces coelicolor TamR in central metabolism

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