Erratum to: The tetraheme cytochrome from Shewanella oneidensis MR-1 shows thermodynamic bias for functional specificity of the hemes

ABSTRACT Two abundant, low-redox-potential cytochromesc were purified from the facultative anaerobeShewanella oneidensis strain MR1 grown anaerobically with fumarate. The small cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. The small cytochrome c contains 91 residues and four heme binding sites. It is most similar to the cytochromes c fromShewanella frigidimarina (formerly Shewanella putrefaciens) NCIMB400 and the unclassified bacterial strain H1R (64 and 55% identity, respectively). The amount of the small tetraheme cytochrome is regulated by anaerobiosis, but not by fumarate. The larger of the two low-potential cytochromes contains tetraheme and flavin domains and is regulated by anaerobiosis and by fumarate and thus most nearly corresponds to the flavocytochromec-fumarate reductase previously characterized fromS. frigidimarina to which it is 59% identical. However, the genetic context of the cytochrome genes is not the same for the twoShewanella species, and they are not located in multicistronic operons. The small cytochrome c and the cytochrome domain of the flavocytochrome c are also homologous, showing 34% identity. Structural comparison shows that theShewanella tetraheme cytochromes are not related to theDesulfovibrio cytochromes c 3but define a new folding motif for small multiheme cytochromesc.

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A directional electron transfer regulator based on heme-chain architecture in the small tetraheme cytochrome c from Shewanella oneidensis

FEBS Letters ◽

10.1016/s0014-5793(02)03696-7 ◽

2002 ◽

Vol 532 (3) ◽

pp. 333-337 ◽

Cited By ~ 22

Author(s):

Erisa Harada ◽

Jiro Kumagai ◽

Kiyoshi Ozawa ◽

Shinichiro Imabayashi ◽

Alexandre S Tsapin ◽

...

Keyword(s):

Electron Transfer ◽

Cytochrome C ◽

Shewanella Oneidensis ◽

Chain Architecture ◽

Tetraheme Cytochrome ◽

Small Tetraheme Cytochrome

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Evidence for quinol oxidase activity of ImoA, a novel NapC/NirT family protein from the neutrophilic Fe(II) oxidizing bacterium Sideroxydans lithotrophicus ES-1

10.1101/2022.01.10.475773 ◽

2022 ◽

Author(s):

Abhiney Jain ◽

Anaísa Coelho ◽

Joana Madjarov ◽

Smilja Todorovic ◽

Ricardo O. Louro ◽

...

Keyword(s):

Electron Flow ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Plasmid Vector ◽

Spectroscopic Characterization ◽

Quinone Reductase ◽

Inner Membrane ◽

Quinol Oxidase ◽

Wide Range ◽

Tetraheme Cytochrome

The freshwater chemolithoautotrophic Gram-negative bacterium Sideroxydans lithotrophicus ES-1 oxidizes Fe(II) at the cell surface. In this organism, it is proposed that the monoheme cytochrome MtoD from the Mto pathway transfer electrons across the periplasm to an inner membrane NapC/NirT family tetraheme cytochrome encoded by Slit_2495, for which we propose the name ImoA (inner membrane oxidoreductase). ImoA has been proposed to function as the quinone reductase, receiving electrons from iron oxidizing extracellular electron uptake pathway to reduce the quinone pool. In this study, ImoA was cloned on a pBAD plasmid vector and overexpressed in Escherichia coli. Biochemical and spectroscopic characterization of the purified ImoA reveals that this 26.5 kDa cytochrome contains one high-spin and three low-spin hemes. Our data show that ImoA can function as a quinol oxidase and is able to functionally replace CymA, a related NapC/NirT family tetraheme cytochrome required for anaerobic respiration of a wide range of substrates by Shewanella oneidensis. We demonstrate that ImoA can transfer electrons to different periplasmic proteins from S. oneidensis including STC and FccA, but in a manner that is distinct from that of CymA. Phylogenetic analysis shows that ImoA is clustered closer to NirT sequences than to CymA. This study suggests that ImoA functions as a quinol oxidase in S. oneidensis and raises questions about the directionality and/or reversibility of electron flow through the Mto pathway in S. lithotrophicus ES-1.

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Vanadium(V) Reduction by Shewanella oneidensis MR-1 Requires Menaquinone and Cytochromes from the Cytoplasmic and Outer Membranes

Applied and Environmental Microbiology ◽

10.1128/aem.70.3.1405-1412.2004 ◽

2004 ◽

Vol 70 (3) ◽

pp. 1405-1412 ◽

Cited By ~ 50

Author(s):

Judith M. Myers ◽

William E. Antholine ◽

Charles R. Myers

Keyword(s):

Electron Transport ◽

Shewanella Oneidensis ◽

Anaerobic Growth ◽

Metal Species ◽

Resonance Spectroscopy ◽

Transport Chain ◽

Respiratory Plasticity ◽

Cell Components ◽

Tetraheme Cytochrome ◽

Membrane Components

ABSTRACT The metal-reducing bacterium Shewanella oneidensis MR-1 displays remarkable anaerobic respiratory plasticity, which is reflected in the extensive number of electron transport components encoded in its genome. In these studies, several cell components required for the reduction of vanadium(V) were determined. V(V) reduction is mediated by an electron transport chain which includes cytoplasmic membrane components (menaquinone and the tetraheme cytochrome CymA) and the outer membrane (OM) cytochrome OmcB. A partial role for the OM cytochrome OmcA was evident. Electron spin resonance spectroscopy demonstrated that V(V) was reduced to V(IV). V(V) reduction did not support anaerobic growth. This is the first report delineating specific electron transport components that are required for V(V) reduction and of a role for OM cytochromes in the reduction of a soluble metal species.

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The cymA Gene, Encoding a Tetraheme c-Type Cytochrome, Is Required for Arsenate Respiration in Shewanella Species

Journal of Bacteriology ◽

10.1128/jb.01698-06 ◽

2007 ◽

Vol 189 (6) ◽

pp. 2283-2290 ◽

Cited By ~ 54

Author(s):

Julie N. Murphy ◽

Chad W. Saltikov

Keyword(s):

Complex Analysis ◽

Shewanella Oneidensis ◽

Site Directed Mutagenesis ◽

Gene Encoding ◽

Terminal Electron Acceptor ◽

Binding Motifs ◽

Shewanella Species ◽

Arsenate Respiration ◽

Tetraheme Cytochrome ◽

Membrane Anchoring

ABSTRACT In Shewanella sp. strain ANA-3, utilization of arsenate as a terminal electron acceptor is conferred by a two-gene operon, arrAB, which lacks a gene encoding a membrane-anchoring subunit for the soluble ArrAB protein complex. Analysis of the genome sequence of Shewanella putrefaciens strain CN-32 showed that it also contained the same arrAB operon with 100% nucleotide identity. Here, we report that CN-32 respires arsenate and that this metabolism is dependent on arrA and an additional gene encoding a membrane-associated tetraheme c-type cytochrome, cymA. Deletion of cymA in ANA-3 also eliminated growth on and reduction of arsenate. The ΔcymA strains of CN-32 and ANA-3 negatively affected the reduction of Fe(III) and Mn(IV) but not growth on nitrate. Unlike the CN-32 ΔcymA strain, growth on fumarate was absent in the ΔcymA strain of ANA-3. Both homologous and heterologous complementation of cymA in trans restored growth on arsenate in ΔcymA strains of both CN-32 and ANA-3. Transcription patterns of cymA showed that it was induced under anaerobic conditions in the presence of fumarate and arsenate. Nitrate-grown cells exhibited the greatest level of cymA expression in both wild-type strains. Lastly, site-directed mutagenesis of the first Cys to Ser in each of the four CXXCH c-heme binding motifs of the CN-32 CymA nearly eliminated growth on and reduction of arsenate. Together, these results indicate that the biochemical mechanism of arsenate respiration and reduction requires the interactions of ArrAB with a membrane-associated tetraheme cytochrome, which in the non-arsenate-respiring Shewanella species Shewanella oneidensis strain MR-1, has pleiotropic effects on Fe(III), Mn(IV), dimethyl sulfoxide, nitrate, nitrite, and fumarate respiration.

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Structural modeling of an outer membrane electron conduit from a metal-reducing bacterium suggests electron transfer via periplasmic redox partners

Journal of Biological Chemistry ◽

10.1074/jbc.ra118.001850 ◽

2018 ◽

Vol 293 (21) ◽

pp. 8103-8112 ◽

Cited By ~ 23

Author(s):

Marcus J. Edwards ◽

Gaye F. White ◽

Colin W. Lockwood ◽

Matthew C. Lawes ◽

Anne Martel ◽

...

Keyword(s):

Electron Transfer ◽

Outer Membrane ◽

Membrane Surface ◽

Shewanella Oneidensis ◽

Direct Interaction ◽

Electron Acceptors ◽

Scattering Data ◽

Redox Partners ◽

Mediated Electron Transfer ◽

Tetraheme Cytochrome

Many subsurface microorganisms couple their metabolism to the reduction or oxidation of extracellular substrates. For example, anaerobic mineral-respiring bacteria can use external metal oxides as terminal electron acceptors during respiration. Porin–cytochrome complexes facilitate the movement of electrons generated through intracellular catabolic processes across the bacterial outer membrane to these terminal electron acceptors. In the mineral-reducing model bacterium Shewanella oneidensis MR-1, this complex is composed of two decaheme cytochromes (MtrA and MtrC) and an outer-membrane β-barrel (MtrB). However, the structures and mechanisms by which porin–cytochrome complexes transfer electrons are unknown. Here, we used small-angle neutron scattering (SANS) to study the molecular structure of the transmembrane complexes MtrAB and MtrCAB. Ab initio modeling of the scattering data yielded a molecular envelope with dimensions of ∼105 × 60 × 35 Å for MtrAB and ∼170 × 60 × 45 Å for MtrCAB. The shapes of these molecular envelopes suggested that MtrC interacts with the surface of MtrAB, extending ∼70 Å from the membrane surface and allowing the terminal hemes to interact with both MtrAB and an extracellular acceptor. The data also reveal that MtrA fully extends through the length of MtrB, with ∼30 Å being exposed into the periplasm. Proteoliposome models containing membrane-associated MtrCAB and internalized small tetraheme cytochrome (STC) indicate that MtrCAB could reduce Fe(III) citrate with STC as an electron donor, disclosing a direct interaction between MtrCAB and STC. Taken together, both structural and proteoliposome experiments support porin–cytochrome–mediated electron transfer via periplasmic cytochromes such as STC.

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