Membrane topology of the chromate transporter ChrA of<i>Pseudomonas aeruginosa</i>

Jiménez-Mejía, Rafael; Campos-Garcı́a, Jesús; Cervantes, Carlos

doi:10.1111/j.1574-6968.2006.00386.x

Cited by 27 publications

(21 citation statements)

References 30 publications

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“…(Desai et al, 2008), Serratia marcescens (Mondaca et al, 2002), Vogococcus fluvialis (Mistry et al, 2010), Arthrobacter aurescens (Horton et al, 2006), Burkholderia cepacia (Wani et al, 2007), Microbacterium sp. (Pattanapipitpaisal et al, 2001) Beveridge, 2001;Jimenez-Mejia et al, 2006;Rahman et al, 2007) and Pseudomonas ambigua (McLean and Beveridge, 2001). Recently, Ilias et al (2011) reported the reduction of Cr (VI) to Cr (III) in the presence of Staphylococcus aureus and Pediococcus pentosaceus isolated from tannery effluents.…”

Section: Introductionmentioning

confidence: 91%

Isolating, screening and applying chromium reducing bacteria to promote growth and yield of okra (Hibiscus esculentus L.) in chromium contaminated soils

Maqbool

Asghar

Shahzad

et al. 2015

Ecotoxicology and Environmental Safety

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Section: Introductionmentioning

confidence: 91%

Isolating, screening and applying chromium reducing bacteria to promote growth and yield of okra (Hibiscus esculentus L.) in chromium contaminated soils

Maqbool

Asghar

Shahzad

et al. 2015

Ecotoxicology and Environmental Safety

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“…P. aeruginosa ChrA is a 416-aa protein that displays a topology of 13 TMSs (Jímenez-Mejía et al 2006). The ChrA transporter functions as a chemiosmotic pump that extrudes chromate from the cytoplasm using the proton-motive force (Alvarez et al 1999;Pimentel et al 2002) (Fig.…”

Section: Chromate Effluxmentioning

confidence: 98%

Bacterial transport of sulfate, molybdate, and related oxyanions

Díaz-Pérez²,

et al. 2011

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Sulfur is an essential element for microorganisms and it can be obtained from varied compounds, sulfate being the preferred source. The first step for sulfate assimilation, sulfate uptake, has been studied in several bacterial species. This article reviews the properties of different bacterial (and archaeal) transporters for sulfate, molybdate, and related oxyanions. Sulfate uptake is carried out by sulfate permeases that belong to the SulT (CysPTWA), SulP, CysP/(PiT), and CysZ families. The oxyanions molybdate, tungstate, selenate and chromate are structurally related to sulfate. Molybdate is transported mainly by the high-affinity ModABC system and tungstate by the TupABC and WtpABC systems. CysPTWA, ModABC, TupABC, and WtpABC are homologous ATP-binding cassette (ABC)-type transporters with similar organization and properties. Uptake of selenate and chromate oxyanions occurs mainly through sulfate permeases.

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“…Bioreduction of toxic Cr(VI) to non-toxic Cr(III), through chromate reductase enzymes, has been demonstrated in several bacterial species including Pseudomonas sp. (Jimenez-Mejia et al 2006), Bacillus sp., Leucobacter sp. and Exiguobacterium sp.…”

Section: Introductionmentioning

confidence: 99%

Hexavalent chromate reduction by alkaliphilic Amphibacillus sp. KSUCr3 is mediated by copper-dependent membrane-associated Cr(VI) reductase

et al. 2012

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The present study was aimed to localize and characterize hexavalent chromate [Cr(VI)] reductase activity of the extreme alkaliphilic Amphibacillus sp. KSUCr3 (optimal growth pH 10.5). The resting cells were able to reduce about 62 % of the toxic heavy metal Cr(VI) at initial concentration of 200 μM within 30 min. Cell permeabilization resulted in decrease of Cr(VI) reduction in comparison to untreated cells. Enzymatic assays of different sub-cellular fractions of Amphibacillus sp. KSUCr3 demonstrated that the Cr(VI) reductase was mainly associated with the membranous fraction and expressed constitutively. In vitro studies of the crude enzyme indicated that copper ion was essential for Cr(VI) reductase activity. In addition, Ca²⁺ and Mn²⁺ slightly stimulated the chromate reductase activity. Glucose was the best external electron donor, showing enhancement of the enzyme activity by about 3.5-fold. The K (m) and V (max) determined for chromate reductase activity in the membranous fraction were 23.8 μM Cr(VI) and 72 μmol/min/mg of protein, respectively. Cr(VI) reductase activity was maximum at 40 °C and pH 7.0 and it was significantly inhibited in the presence of disulfide reducers (2-mercaptoethanol), ion chelating agent (EDTA), and respiratory inhibitors (CN and Azide). Complete reduction of 100 and 200 μM of Cr(VI) by membrane associated enzyme were observed within 40 and 180 min, respectively. However, it should be noted that biochemical characterization has been done with crude enzyme only, and that final conclusion can only be drawn with the purified enzyme.

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Membrane topology of the chromate transporter ChrA ofPseudomonas aeruginosa

Cited by 27 publications

References 30 publications

Isolating, screening and applying chromium reducing bacteria to promote growth and yield of okra (Hibiscus esculentus L.) in chromium contaminated soils

Isolating, screening and applying chromium reducing bacteria to promote growth and yield of okra (Hibiscus esculentus L.) in chromium contaminated soils

Bacterial transport of sulfate, molybdate, and related oxyanions

Hexavalent chromate reduction by alkaliphilic Amphibacillus sp. KSUCr3 is mediated by copper-dependent membrane-associated Cr(VI) reductase

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