Isolation and Characterization of a Soluble NADPH-Dependent Fe(III) Reductase from
            <i>Geobacter sulfurreducens</i>

Kaufmann, Franz; Lovley, Derek R.

doi:10.1128/jb.183.15.4468-4476.2001

Cited by 58 publications

(51 citation statements)

References 58 publications

(51 reference statements)

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“…The results of this work are consistent with Fe(III) citrate reduction occurring outside the cytoplasm, and suggest that SfrAB is involved in acetate metabolism and does not participate directly in the reduction of Fe(III) chelates, as was previously proposed (Kaufmann & Lovley, 2001). …”

Section: Introductionsupporting

confidence: 79%

“…Spheroplast suspension assays were performed identically except for the substitution of the basal wash medium with spheroplast wash buffer containing 350 mM sucrose (see above Construction of an SfrAB-null (DsfrAB : : kan) strain. SfrAB is encoded by a two-gene cluster (sfrBA), consisting of the sfrB gene followed by a 126 bp intergenic region and the sfrA gene (Kaufmann & Lovley, 2001;Methé et al, 2003). In order to disrupt the sfrBA cluster by homologous recombination, a linear DNA fragment, consisting of a kanamycin resistance cassette flanked by the first 0.58 kb of the sfrB gene and the last 0.54 kb of the sfrA gene, was constructed.…”

Section: Methodsmentioning

confidence: 99%

“…Intact-cell suspensions were prepared as previously described Leang et al, 2003). Because previously published methods for the production of G. sulfurreducens spheroplasts (Galushko & Schink, 2000;Kaufmann & Lovley, 2001) failed to yield homogeneous spheroplast preparations reproducibly, the spheroplast preparation protocol of Witholt et al (1976) was adapted for use in G. sulfurreducens. Intact cells were harvested by centrifugation for 15 min at 6000 g and resuspended iñ 100 ml spheroplast wash medium, consisting of (g l 21 ): 0.42 KH 2 PO 4 , 0.22 K 2 HPO 4 , 0.38 KCl, 4.96 NaCl, 1.8 NaHCO 3 and 0.5 Na 2 CO 3 .…”

Section: Methodsmentioning

confidence: 99%

“…Biochemical studies performed in G. sulfurreducens have provided conflicting information regarding the site of Fe(III) chelate reduction. Purification of SfrAB, a twosubunit complex capable of catalysing the NADPHdependent reduction of Fe(III)-NTA, from the soluble fraction (Kaufmann & Lovley, 2001) suggested that Fe(III) chelates might be reduced within the cytoplasm. Membrane-bound, multi-subunit complexes with the capacity to catalyse NADH-dependent Fe(III)-NTA reduction (Gaspard et al, 1998;Magnuson et al, 2000) have also been isolated, one of which was reported to be associated the outer-membrane fraction (Gaspard et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

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Involvement of Geobacter sulfurreducens SfrAB in acetate metabolism rather than intracellular, respiration-linked Fe(III) citrate reduction

et al. 2007

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A soluble ferric reductase, SfrAB, which catalysed the NADPH-dependent reduction of chelated Fe(III), was previously purified from the dissimilatory Fe(III)-reducing micro-organism Geobacter sulfurreducens, suggesting that reduction of chelated forms of Fe(III) might be cytoplasmic. However, metabolically active spheroplast suspensions could not catalyse acetate-dependent Fe(III) citrate reduction, indicating that periplasmic and/or outer-membrane components were required for Fe(III) citrate reduction. Furthermore, phenotypic analysis of an SfrAB knockout mutant suggested that SfrAB was involved in acetate metabolism rather than respiration-linked Fe(III) reduction. The mutant could not grow via the reduction of either Fe(III) citrate or fumarate when acetate was the electron donor but could grow with either acceptor if either hydrogen or formate served as the electron donor. Following prolonged incubation in acetate : fumarate medium in the absence of hydrogen and formate, an 'acetate-adapted' SfrAB-null strain was isolated that was capable of growth on acetate : fumarate medium but not acetate : Fe(III) citrate medium. Comparison of gene expression in this strain with that of the wild-type revealed upregulation of a potential NADPH-dependent ferredoxin oxidoreductase as well as genes involved in energy generation and amino acid uptake, suggesting that NADPH homeostasis and the tricarboxylic acid (TCA) cycle were perturbed in the 'acetate-adapted' SfrAB-null strain. Membrane and soluble fractions prepared from the 'acetate-adapted' strain were depleted of NADPH-dependent Fe(III), viologen and quinone reductase activities. These results indicate that cytoplasmic, respiration-linked reduction of Fe(III) by SfrAB in vivo is unlikely and suggest that deleting SfrAB may interfere with growth via acetate oxidation by interfering with NADP regeneration.

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Section: Introductionsupporting

confidence: 79%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Involvement of Geobacter sulfurreducens SfrAB in acetate metabolism rather than intracellular, respiration-linked Fe(III) citrate reduction

et al. 2007

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“…Some are highly specific for either NADH/NAD + or NADPH/NADP + , while others can use both with varying degrees of preference for one over the other. For example, the previously mentioned D-hydroxyisovalerate dehydrogenase of Fusarium sambucinum, as well as the soluble NADPH-dependent Fe(III) reductase from Geobacter sulfurreducens, are highly specific for NADPH/ NADP + and are unable to accept NADH/NAD + [58,61]. At the opposite extreme, the E. coli aldo-keto reductase encoded by the ydjG gene is highly specific for NADH/NAD + and is unable to accept NADPH/ NADP.…”

Section: Nad(p)h-dependent Oxidoreductases Nadph-dependent Oxidoreducmentioning

confidence: 99%

Review of NAD(P)H-dependent oxidoreductases: Properties, engineering and application

Vidal

Kelly

Mordaka

et al. 2018

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

212

137

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A B S T R A C T NAD(P)H-dependent oxidoreductases catalyze the reduction or oxidation of a substrate coupled to the oxidation or reduction, respectively, of a nicotinamide adenine dinucleotide cofactor NAD(P)H or NAD(P) + . NAD(P)Hdependent oxidoreductases catalyze a large variety of reactions and play a pivotal role in many central metabolic pathways. Due to the high activity, regiospecificity and stereospecificity with which they catalyze redox reactions, they have been used as key components in a wide range of applications, including substrate utilization, the synthesis of chemicals, biodegradation and detoxification. There is great interest in tailoring NAD(P)H-dependent oxidoreductases to make them more suitable for particular applications. Here, we review the main properties and classes of NAD(P)H-dependent oxidoreductases, the types of reactions they catalyze, some of the main protein engineering techniques used to modify their properties and some interesting examples of their modification and application.

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A novel method for determination of a time period for stabilization of power generation of microbial fuel cell with effect of microorganisms

et al. 2019

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Summary Microbial fuel cells (MFCs) are quickly gaining traction in the mainstream industry due to their capabilities in simultaneous power generation and wastewater purification. They use bacteria like Shewanella and Geobacter as primary units for the same. However, their power generation capabilities are limited by a lack of stability in certain configurations. For the development of appropriate power storage and management systems, this instability must be investigated. Therefore, the present study proposes the artificial intelligence (AI) methodology of artificial neural search (ANS) networks to predict the period for stabilization of power generation of microbial fuel cell in the presence of microorganisms. An output voltage has been measured as a function of time (approximately 1600 h). A stabilization period of power generation has been predicted from the slope obtained from the graph of voltage vs time. The analysis of the ANS model indicated that the power generation stabilization has occurred between 12th and 16th weeks. Experiments were then performed to validate the findings from the ANS model. This may serve as an indication for the development of energy management and storage systems that can account for the trends observed during this study

show abstract

Isolation and Characterization of a Soluble NADPH-Dependent Fe(III) Reductase from Geobacter sulfurreducens

Cited by 58 publications

References 58 publications

Involvement of Geobacter sulfurreducens SfrAB in acetate metabolism rather than intracellular, respiration-linked Fe(III) citrate reduction

Involvement of Geobacter sulfurreducens SfrAB in acetate metabolism rather than intracellular, respiration-linked Fe(III) citrate reduction

Review of NAD(P)H-dependent oxidoreductases: Properties, engineering and application

A novel method for determination of a time period for stabilization of power generation of microbial fuel cell with effect of microorganisms

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