Thermodynamics of Electron Flow in the Bacterial Deca-heme Cytochrome MtrF
Electron transporting multiheme cytochromes are essential to the metabolism of microbes that inhabit soils and carry out important biogeochemical processes. Recently the first crystal structure of a prototype bacterial deca-heme cytochrome (MtrF) has been resolved and its electrochemistry characterized. However, the molecular details of electron conductance along heme chains in the cytochrome are difficult to access via experiment due to the nearly identical chemical nature of the heme cofactors. Here we employ large-scale molecular dynamics simulations to compute the reduction potentials of the ten hemes of MtrF in aqueous solution. We find that as a whole they fall within a range of about 0.3 V in agreement with experiment. Individual reduction potentials give rise to a free energy profile for electron conduction that is approximately symmetric with respect to the center of the protein. Our calculations indicate that there is no significant potential bias along the orthogonal octa- and tetra-heme chains suggesting that under aqueous conditions MtrF is a nearly reversible two-dimensional conductor.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1047356
- Report Number(s):
- PNNL-SA-86515; JACSAT; 46203; KP1702030; TRN: US201216%%215
- Journal Information:
- Journal of the American Chemical Society, Vol. 134, Issue 24; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
60 APPLIED LIFE SCIENCES
54 ENVIRONMENTAL SCIENCES
AQUEOUS SOLUTIONS
CRYSTAL STRUCTURE
CYTOCHROMES
ELECTROCHEMISTRY
ELECTRONS
FREE ENERGY
HEME
METABOLISM
MOLECULAR DYNAMICS METHOD
POTENTIALS
RANGE
REDUCTION
RISE
SOILS
THERMODYNAMICS
Electron transfer
c-type cytochrome
molecular dynamics
Shewanella oneidensis
Environmental Molecular Sciences Laboratory