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The ‘porin–cytochrome’ model for microbe‐to‐mineral electron transfer
Author(s) -
Richardson David J.,
Butt Julea N.,
Fredrickson Jim K.,
Zachara John M.,
Shi Liang,
Edwards Marcus J.,
White Gaye,
Baiden Nanakow,
Gates Andrew J.,
Marritt Sophie J.,
Clarke Thomas A.
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08088.x
Subject(s) - porin , electron transport chain , bacterial outer membrane , electron transfer , biology , extracellular , shewanella , cytochrome , shewanella oneidensis , bacteria , biophysics , electron , anaerobic respiration , biochemistry , microbiology and biotechnology , chemistry , photochemistry , physics , enzyme , genetics , gene , escherichia coli , quantum mechanics
Summary Many species of bacteria can couple anaerobic growth to the respiratory reduction of insoluble minerals containing Fe(III) or Mn(III/IV). It has been suggested that in Shewanella species electrons cross the outer membrane to extracellular substrates via ‘porin–cytochrome’ electron transport modules. The molecular structure of an outer‐membrane extracellular‐facing deca‐haem terminus for such a module has recently been resolved. It is debated how, once outside the cells, electrons are transferred from outer‐membrane cytochromes to insoluble electron sinks. This may occur directly or by assemblies of cytochromes, perhaps functioning as ‘nanowires’, or via electron shuttles. Here we review recent work in this field and explore whether it allows for unification of the electron transport mechanisms supporting extracellular mineral respiration in Shewanella that may extend into other genera of Gram‐negative bacteria.