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Magnetite compensates for the lack of a pilin‐associated c ‐type cytochrome in extracellular electron exchange
Author(s) -
Liu Fanghua,
Rotaru AmeliaElena,
Shrestha Pravin M.,
Malvankar Nikhil S.,
Nevin Kelly P.,
Lovley Derek R.
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12485
Subject(s) - pilin , magnetite , electron transfer , extracellular , pilus , geobacter sulfurreducens , biology , cytochrome , heme , biophysics , electron transport chain , geobacter , microbiology and biotechnology , cytochrome c , biochemistry , bacteria , chemistry , biofilm , enzyme , gene , photochemistry , mitochondrion , genetics , paleontology , virulence
Summary Nanoscale magnetite can facilitate microbial extracellular electron transfer that plays an important role in biogeochemical cycles, bioremediation and several bioenergy strategies, but the mechanisms for the stimulation of extracellular electron transfer are poorly understood. Further investigation revealed that magnetite attached to the electrically conductive pili of G eobacter species in a manner reminiscent of the association of the multi‐heme c ‐type cytochrome OmcS with the pili of G eobacter sulfurreducens . Magnetite conferred extracellular electron capabilities on an OmcS ‐deficient strain unable to participate in interspecies electron transfer or Fe ( III ) oxide reduction. In the presence of magnetite wild‐type cells repressed expression of the OmcS gene, suggesting that cells might need to produce less OmcS when magnetite was available. The finding that magnetite can compensate for the lack of the electron transfer functions of a multi‐heme c ‐type cytochrome has implications not only for the function of modern microbes, but also for the early evolution of microbial electron transport mechanisms.