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OmcS Oxidoreductase
OmcS nanowires (Geobacter nanowires) are conductive filaments found in some species of bacteria, including ''Geobacter sulfurreducens'', where they catalyze the transfer of electrons. They are multi heme c-Type cytochrome Cytochromes are redox-active proteins containing a heme, with a central Fe atom at its core, as a cofactor. They are involved in electron transport chain and redox catalysis. They are classified according to the type of heme and its mode of bin ...s localized outside of the cell of some exoelectrogenic bacterial species, serving as mediator of extracellular electron transfer from cells to Fe(III) oxides and other extracellular electron acceptors. OmcS3D structure has a core of six low-spin bis-histidinyl hexacoordinated heme groups inside a sinusoidal filament ~5-7.4 nm in diameter, with 46.7 Å rise per subunit and 4.3 subunits per turn. The six-heme packing motif of OmcS is identical to that seen in a ~3 nm diameter cytochrome nanowire, OmcE3D structure, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Nanowires
Bacterial nanowires (also known as microbial nanowires) are electrically conductive appendages produced by a number of bacteria most notably from (but not exclusive to) the ''Geobacter'' and ''Shewanella'' genera. Conductive nanowires have also been confirmed in the oxygenic cyanobacterium ''Synechocystis'' PCC6803 and a thermophilic, methanogenic coculture consisting of '' Pelotomaculum thermopropionicum'' and '' Methanothermobacter thermoautotrophicus''. From physiological and functional perspectives, bacterial nanowires are diverse. The precise role microbial nanowires play in their biological systems has not been fully realized, but several proposed functions exist. Outside of a naturally occurring environment, bacterial nanowires have shown potential to be useful in several fields, notably the bioenergy and bioremediation industries. Physiology ''Geobacter'' nanowires were originally thought to be modified pili, which are used to establish connections to terminal electron a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filamentation
Filamentation is the anomalous growth of certain bacteria, such as ''Escherichia coli'', in which cells continue to elongate but do not divide (no septa formation). The cells that result from elongation without division have multiple chromosomal copies. In the absence of antibiotics or other stressors, filamentation occurs at a low frequency in bacterial populations (4–8% short filaments and 0–5% long filaments in 1- to 8-hour cultures). The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult. Filamentation is also thought to protect bacteria from antibiotics, and is associated with other aspects of bacterial virulence such as biofilm formation. The number and length of filaments within a bacterial population increases when the bacteria are exposed to different physical, chemical and biological agents (e.g. UV light, DNA synthesis-inhibiting antibiotics, bacteriophages). This is termed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geobacter Sulfurreducens
''Geobacter sulfurreducens'' is a gram-negative metal and sulphur-reducing proteobacterium. It is rod-shaped, obligately anaerobic, non-fermentative, has flagellum and type four pili, and is closely related to ''Geobacter metallireducens''. ''Geobacter sulfurreducens'' is an anaerobic species of bacteria that comes from the family of bacteria called Geobacteraceae. Under the genus of Geobacter, ''G. sulfurreducens'' is one out of twenty different species. The Geobacter genus was discovered by Derek R. Lovley in 1987. ''G. sulfurreducens'' was first isolated in Norman, Oklahoma, USA from materials found around the surface of a contaminated ditch. Characteristics ''Geobacter sulfurreducens'' is a rod-shaped microbe with a gram-negative cell wall. Geobacter is known as a type of bacteria that is able to conduct levels of electricity, and the species ''G. sulfurreducens'' is also known as “electricigens” due to their ability to create an electric current and produce electrici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heme
Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consisting of an iron ion coordinated to a porphyrin acting as a tetradentate ligand, and to one or two axial ligands." The definition is loose, and many depictions omit the axial ligands. Among the metalloporphyrins deployed by metalloproteins as prosthetic groups, heme is one of the most widely used and defines a family of proteins known as hemoproteins. Hemes are most commonly recognized as components of hemoglobin, the red pigment in blood, but are also found in a number of other biologically important hemoproteins such as myoglobin, cytochromes, catalases, heme peroxidase, and endothelial nitric oxide synthase. The word ''haem'' is derived from Greek ''haima'' meaning "blood". Function Hemoproteins have diverse biological functions incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome
Cytochromes are redox-active proteins containing a heme, with a central Fe atom at its core, as a cofactor. They are involved in electron transport chain and redox catalysis. They are classified according to the type of heme and its mode of binding. Four varieties are recognized by the International Union of Biochemistry and Molecular Biology (IUBMB), cytochromes a, cytochromes b, cytochromes c and cytochrome d. Cytochrome function is linked to the reversible redox change from ferrous (Fe(II)) to the ferric (Fe(III)) oxidation state of the iron found in the heme core. In addition to the classification by the IUBMB into four cytochrome classes, several additional classifications such as cytochrome o and cytochrome P450 can be found in biochemical literature. History Cytochromes were initially described in 1884 by Charles Alexander MacMunn as respiratory pigments (myohematin or histohematin). In the 1920s, Keilin rediscovered these respiratory pigments and named them the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial Fuel Cell
Microbial fuel cell (MFC) is a type of bioelectrochemical fuel cell system that generates electric current by diverting electrons produced from the microbial oxidation of reduced compounds (also known as fuel or electron donor) on the anode to oxidized compounds such as oxygen (also known as oxidizing agent or electron acceptor) on the cathode through an external electrical circuit. MFCs can be grouped into two general categories: mediated and unmediated. The first MFCs, demonstrated in the early 20th century, used a mediator: a chemical that transfers electrons from the bacteria in the cell to the anode. Unmediated MFCs emerged in the 1970s; in this type of MFC the bacteria typically have electrochemically active redox proteins such as cytochromes on their outer membrane that can transfer electrons directly to the anode. In the 21st century MFCs have started to find commercial use in wastewater treatment. History The idea of using microbes to produce electricity was conceived in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
