High-affinity binding and direct electron transfer to solid metals by the Shewanella oneidensis MR-1 outer membrane c-type cytochrome OmcA.
The purified outer membrane bacterial protein OmcA binds densely to the surface of hematite (Fe2O3), permitting direct electron transfer to this solid mineral to reduce Fe (III) with an electron flux of about 1013 electrons /cm2/s. In the presence of hematite, there is a substantial increase in the amplitude of internal protein motions that correlate with metal reduction. Binding is highly favorable, with a partition coefficient of approximately 2 x 105 (DeltaGo' = -28 kJ/mol), where approximately 1014 OmcA proteins bind per cm2 to the solid metal surface, indicating the utility of using purified OmcA in the construction of a biofuel cell.
Xiong
Yijia
Y
Division of Biological Sciences and Environmental Molecular Science Laboratory, Biogeochemistry Grand Challenge Program, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Shi
Liang
L
Chen
Baowei
B
Mayer
M Uljana
MU
Lower
Brian H
BH
Londer
Yuri
Y
Bose
Saumyaditya
S
Hochella
Michael F
MF
Fredrickson
James K
JK
Squier
Thomas C
TC
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D045304:Cytochromes c / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D011485:Protein Binding; D020592:Shewanella / Q000201:enzymology*; D013050:Spectrometry, Fluorescence
D001426:Bacterial Proteins; D008565:Membrane Proteins; D008670:Metals; D045304:Cytochromes c