The respiration of metals by the bacterium Geobacter sulfurreducens requires electrons generated metabolism to pass from interior cell electron acceptors beyond membranes. G. inner membrane multiheme c-type cytochrome ImcH is required for extracellular with redox potentials greater than -0.1 V vs. SHE, but not essential transfer lower potential acceptors. In contrast, deletion cbcL, encoding an protein consisting b-type and domains, severely affected reduction low such as Fe(III)-oxides...

Dissimilatory metal-reducing bacteria, such as Geobacter sulfurreducens, transfer electrons beyond their outer membranes to Fe(III) and Mn(IV) oxides, heavy metals, electrodes in electrochemical devices. In the environment, metal acceptors exist multiple chelated insoluble forms that span a range of redox potentials offer different amounts available energy. Despite this, bacteria have not been shown alter electron strategies take advantage these energy differences. Disruption imcH, encoding...

Gram-negative metal-reducing bacteria utilize electron conduits, chains of redox proteins spanning the outer membrane, to transfer electrons extracellular surface. Only one pathway for across membrane Geobacter sulfurreducens has been linked Fe(III) reduction. However, G. is able respire a wide array substrates. Here we present first combinatorial genetic analysis five different conduits via creation new markerless deletion strains and complementation vectors. Multiple conduit gene clusters...

While early genetic and low-resolution structural observations suggested that extracellular conductive filaments on metal-reducing organisms such as

The gene encoding the unique soluble acyl-acyl carrier protein synthetase (AasS) of bioluminescent Vibrio harveyi strain B392 has been isolated by expression cloning in Escherichia coli. This enzyme catalyzes ATP-dependent acylation thiol acyl (ACP) with fatty acids chain lengths from C4 to C18. (called aasS) encodes a 60 kDa, hexahistidine-tagged version which was readily expressed E. coli and purified large quantities. Surprisingly, sequence encoded significantly more similar that an...

Reaching a depth of 713 m below the surface, Soudan Underground Iron Mine (Soudan, MN, USA) transects massive Archaean (2.7 Ga) banded iron formation, providing remarkably accessible window into terrestrial deep biosphere. Despite organic carbon limitation, metal-reducing microbial communities are present in potentially ancient anoxic brines continuously emanating from exploratory boreholes on Level 27. Using graphite electrodes deposited situ as bait, we electrochemically enriched and...

ABSTRACT Metal reduction by members of the Geobacteraceae is encoded multiple gene clusters, and study extracellular electron transfer often requires biofilm development on surfaces. Genetic tools that utilize polar antibiotic cassette insertions limit mutant construction complementation. In addition, unstable plasmids create metabolic burdens slow growth, presence antibiotics such as kanamycin can interfere with rate extent Geobacter growth. We report here genetic system improvements for...

ABSTRACT Geobacter sulfurreducens generates electrical current by coupling intracellular oxidation of organic acids to the reduction proteins on cell surface that are able interface with electrodes. This ability is attributed bacterium's capacity respire other extracellular electron acceptors require contact, such as insoluble metal oxides. To directly investigate genetic basis electrode-based respiration, we constructed transposon-insertion sequencing (Tn-Seq) libraries for growth, soluble...

Geobacter sulfurreducens utilizes extracellular electron acceptors such as Mn(IV), Fe(III), syntrophic partners, and electrodes that vary from +0.4 to -0.3 V versus standard hydrogen electrode (SHE), representing a potential energy span should require highly branched transfer chain. Here we describe CbcBA, bc-type cytochrome essential near the thermodynamic limit of respiration when acetate is donor. Mutants-lacking cbcBA ceased Fe(III) reduction at -0.21 SHE, could not electrons between...

In the homoacetogenic bacterium Sporomusa ovata, phenol and p-cresol are converted into α-ribotides, which incorporated biologically active cobamides (Cbas) whose lower ligand bases do not form axial co-ordination bonds with cobalt ion of corrin ring. Here we report identity two S. ovata genes that encode an enzyme transfers phosphoribosyl group nicotinate mononucleotide (NaMN) to or p-cresol, yielding α-O-glycosidic ribotides. The alluded were named arsA arsB (for alpha-ribotide synthesis),...

Acetyl-coenzyme A synthetase (Acs) activates acetate into acetyl-coenzyme (Ac-CoA) in most cells. In Salmonella enterica, acs expression and Acs activity are controlled. It is unclear why the sirtuin-dependent protein acylation/deacylation system (SDPADS) controls of Acs. Here we show that, during growth on 10 mM acetate, acs(+) induction a S. enterica strain that cannot acetylate (i.e. inactivate) leads to arrest, condition correlates with drop energy charge (0.17) acetylation-deficient...

A newfound signaling pathway employs a GGDEF enzyme with unique activity compared to the majority of homologs associated bacterial cyclic di-GMP signaling. This system provides rare opportunity study how proteins natively gain distinct function. Using genetic knockouts, riboswitch reporters, and RNA-Seq, we show that GacA, Hypr in Geobacter sulfurreducens, specifically regulates GMP-AMP (3',3'-cGAMP) levels vivo stimulate gene expression metal reduction separate from electricity production....

Reduction of extracellular acceptors requires electron transfer across the periplasm. In Geobacter sulfurreducens, three separate cytoplasmic membrane cytochromes are utilized depending on redox potential, and at least five cytochrome conduits span outer membrane. Because G. sulfurreducens produces 5 structurally similar triheme periplasmic (PpcABCDE) that differ in expression level, midpoint heme biochemistry, many hypotheses propose distinct carriers could be used for specific potentials,...

Although the Escherichia coli fatty acid synthesis (FAS) pathway is best studied type II system, a major experimental limitation has been inability to feed intermediates into in vivo because exogenously supplied free acids are not efficiently converted acyl−acyl carrier protein (ACP) thioesters required by pathway. We report that expression of Vibrio harveyi acyl-ACP synthetase (AasS), soluble cytosolic enzyme ligates ACP form acyl-ACPs, allows exogenous enter E. The incorporated intact and...

Abstract Integral membrane aspartic acid proteases are receiving growing recognition for their fundamental roles in cellular physiology of eukaryotes and prokaryotes, may be medically important pharmaceutical targets. The G ram‐negative P seudomonas aeruginosa PilD the archaeal M ethanococcus voltae FlaK were synthesized presence unilamellar liposomes a cell‐free translation system. Cosynthesis with its full‐length substrate, PilA, or FlaB2, led to complete cleavage substrate signal...

Cobamides (Cbas) are cobalt (Co) containing tetrapyrrole-derivatives involved in enzyme-catalyzed carbon skeleton rearrangements, methyl-group transfers, and reductive dehalogenation. The biosynthesis of cobamides is complex only performed by some bacteria achaea. have an upper (Coβ) ligand (5′-deoxyadenosyl or methyl) a lower (Coα) base that contribute to the axial Co coordinations. identity Coα varies depending on organism synthesizing Cbas. homoacetogenic bacterium Sporomusa ovata...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInhibitors of cholesterol biosynthesis. 1. 3,5-Dihydroxy-7-(N-imidazolyl)-6-heptenoates and -heptanoates, a novel series 3-hydroxy-3-methylglutarate-CoA reductase inhibitorsChuen Chan, Esme J. Bailey, C. David Hartley, F. Hayman, Julie L. Hutson, Graham G. A. Inglis, Paul S. Jones, Suzanne E. Keeling, Barrie Kirk, Cite this: Med. Chem. 1993, 36, 23, 3646–3657Publication Date (Print):November 1, 1993Publication History Published online1 May...

Abstract Geobacter sulfurreducens generates electricity by coupling intracellular oxidation of organic acids with electron transfer to the cell exterior, while maintaining a conductive connection electrode surfaces. This unique ability has been attributed bacterium’s capacity also respire extracellular terminal acceptors that require contact, such as insoluble metal oxides. To expand molecular understanding generation mechanisms, we constructed transposon mutant (Tn-Seq) libraries for growth...

ABSTRACT Reaching a depth of 713 m below the surface, Soudan Underground Iron Mine (Soudan, Minnesota, USA) transects massive Archaean (2.7 Ga) banded iron formation, providing remarkably accessible window into terrestrial deep biosphere. Despite carbon limitation, metal-reducing microbial communities are present in potentially ancient anoxic brines continuously emanating from exploratory boreholes on Level 27. Using graphite electrodes deposited situ as bait, we enriched and isolated novel...

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to The Soluble Acyl−Acyl Carrier Protein Synthetase of Vibrio harveyi B392 Is Member the Medium Chain Acyl-CoA FamilyYanfang Jiang, Chi Ho Chan, and John E. Cronan*Cite this: Biochemistry 2010, 49, 1, 247Publication Date (Web):December 16, 2009Publication History Received4 December 2009Published online16 inissue 12 January...

The Hypr cGAMP signaling pathway was discovered via the function of riboswitch. In this study, we show development a method for affinity capture followed by sequencing to identify non-coding RNA regions that bind nucleotide signals such as cGAMP. RNAseq affinity-captured riboswitches from Geobacter sulfurreducens transcriptome highlights general challenges remain technique. Furthermore, applying riboswitch reporters in vivo, new growth conditions and transposon mutations affect levels G....

Abstract During extracellular electron transfer, Geobacter sulfurreducens constitutively expresses the bc‐ cytochrome CbcL, yet cells containing only this menaquinone oxidase fail to respire above −0.1 V vs . SHE. By identifying mutations within cbcL that permit growth at higher potentials, we provide evidence is regulated by redox potential. Strains expressing CbcL V205A , V205G and F525Y were capable of with high potential acceptors including Fe(III) citrate, Mn(IV) oxides, electrodes...