Structural and redox properties of mitochondrial cytochrome c co-sorbed with phosphate on hematite (α-Fe2O3) surfaces

Khare, Nidhi; Eggleston, Carrick M.; Lovelace, David M.; Boese, Steven W.

doi:10.1016/j.jcis.2006.07.070

Cited by 27 publications

(18 citation statements)

References 58 publications

(94 reference statements)

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“…In previous studies (Khare et al, 2005(Khare et al, , 2006a with cytochrome c (not from DMRB) and hematite electrodes, we observed redox peaks at the expected potentials for the native state of the protein and, under some circumstances (such as with the addition of denaturant), for unfolded states of the protein as well. Cytochrome c could also be inactivated such that no redox peaks were observed.…”

Section: Voltammetric Characteristicsmentioning

confidence: 57%

Electrochemical interaction of Shewanella oneidensis MR-1 and its outer membrane cytochromes OmcA and MtrC with hematite electrodes

Meitl

Eggleston

Colberg

et al. 2009

Geochimica et Cosmochimica Acta

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130

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Bacterial metal reduction is an important biogeochemical process in anaerobic environments. An understanding of electron transfer pathways from dissimilatory metal-reducing bacteria (DMRB) to solid phase metal (hydr)oxides is important for understanding metal redox cycling in soils and sediments, for utilizing DMRB in bioremedation, and for developing technologies such as microbial fuel cells. Here we hypothesize that the outer membrane cytochromes OmcA and MtrC from Shewanella oneidensis MR-1 are the only terminal reductases capable of direct electron transfer to a hematite working electrode. Cyclic voltammetry (CV) was used to study electron transfer between hematite electrodes and protein films, S. oneidensis MR-1 wild-type cell suspensions, and cytochrome deletion mutants. After controlling for hematite electrode dissolution at negative potential, the midpoint potentials of adsorbed OmcA and MtrC were measured (À201 mV and À163 mV vs. Ag/ AgCl, respectively). Cell suspensions of wild-type MR-1, deletion mutants deficient in OmcA (DomcA), MtrC (DmtrC), and both OmcA and MtrC (DmtrC-DomcA) were also studied; voltammograms for DmtrC-DomcA were indistinguishable from the control. When the control was subtracted from the single deletion mutant voltammograms, redox peaks were consistent with the present cytochrome (i.e., DomcA consistent with MtrC and DmtrC consistent with OmcA). The results indicate that OmcA and MtrC are capable of direct electron exchange with hematite electrodes, consistent with a role as terminal reductases in the S. oneidensis MR-1 anaerobic respiratory pathway involving ferric minerals. There was no evidence for other terminal reductases operating under the conditions investigated. A Marcus-based approach to electron transfer kinetics indicated that the rate constant for electron transfer k et varies from 0.025 s À1 in the absence of a barrier to 63.5 s À1 with a 0.2 eV barrier.

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Section: Voltammetric Characteristicsmentioning

confidence: 57%

Electrochemical interaction of Shewanella oneidensis MR-1 and its outer membrane cytochromes OmcA and MtrC with hematite electrodes

Meitl

Eggleston

Colberg

et al. 2009

Geochimica et Cosmochimica Acta

Self Cite

130

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“…It is known that ions present in protein-soil solutions can interact with both mineral surfaces and proteins to influence surface adsorption capacity as well as the adsorbed protein conformation. For example, monovalent cations in solution can inhibit protein adsorption to mica [29], and phosphate can stabilize protein structure during adsorption [30], as well as retard adsorption and increase the adsorbed protein footprint [31]. In addition, phosphate has been shown to compete with negatively-charged proteins when binding to certain surfaces [32], but conversely, the binding of four proteins to montmorillonite and kaolinite clays increased in phosphate buffer compared to DI water [33].…”

Section: Discussionmentioning

confidence: 99%

Effects of Solution Chemistry and Aging Time on Prion Protein Adsorption and Replication of Soil-Bound Prions

et al. 2011

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Prion interactions with soil may play an important role in the transmission of chronic wasting disease (CWD) and scrapie. Prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. We investigated HY TME prion protein (PrPSc) adsorption to soil minerals in aqueous solutions of phosphate buffered saline (PBS), sodium chloride, calcium chloride, and deionized water using western blotting. The replication efficiency of bound prions following adsorption in these solutions was also evaluated by protein misfolding cyclic amplification (PMCA). Aging studies investigated PrPSc desorption and replication efficiency up to one year following adsorption in PBS or DI water. Results indicate that adsorption solution chemistry can affect subsequent prion replication or desorption ability, especially after incubation periods of 30 d or longer. Observed effects were minor over the short-term (7 d or less). Results of long-term aging experiments demonstrate that unbound prions or prions bound to a diverse range of soil surfaces can readily replicate after one year. Our results suggest that while prion-soil interactions can vary with solution chemistry, prions bound to soil could remain a risk for transmitting prion diseases after months in the environment.

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“…when net charges are minimal, indicate that hydrophobic interactions dominate the attachment to the surface in these cases. Adsorption of cytochrome c from horse heart (pI = 10-10.5) to hematite (pI = 8.4) was limited to a narrow pH range between pH 8.5 and 10 that corresponds to positive charges on the protein and negative charges on hematite [ 63 , 64 ]. In this case, the driving force for surface attachment seemed to be electrostatic interaction.…”

Section: Bioengineered Hematite Pec Cellsmentioning

confidence: 99%

Light Harvesting Proteins for Solar Fuel Generation in Bioengineered Photoelectrochemical Cells

Ihssen¹,

Braun²,

Faccio³

et al. 2014

CPPS

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The sun is the primary energy source of our planet and potentially can supply all societies with more than just their basic energy needs. Demand of electric energy can be satisfied with photovoltaics, however the global demand for fuels is even higher. The direct way to produce the solar fuel hydrogen is by water splitting in photoelectrochemical (PEC) cells, an artificial mimic of photosynthesis. There is currently strong resurging interest for solar fuels produced by PEC cells, but some fundamental technological problems need to be solved to make PEC water splitting an economic, competitive alternative. One of the problems is to provide a low cost, high performing water oxidizing and oxygen evolving photoanode in an environmentally benign setting. Hematite, α-Fe2O3, satisfies many requirements for a good PEC photoanode, but its efficiency is insufficient in its pristine form. A promising strategy for enhancing photocurrent density takes advantage of photosynthetic proteins. In this paper we give an overview of how electrode surfaces in general and hematite photoanodes in particular can be functionalized with light harvesting proteins. Specifically, we demonstrate how low-cost biomaterials such as cyanobacterial phycocyanin and enzymatically produced melanin increase the overall performance of virtually no-cost metal oxide photoanodes in a PEC system. The implementation of biomaterials changes the overall nature of the photoanode assembly in a way that aggressive alkaline electrolytes such as concentrated KOH are not required anymore. Rather, a more environmentally benign and pH neutral electrolyte can be used.

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Structural and redox properties of mitochondrial cytochrome c co-sorbed with phosphate on hematite (α-Fe2O3) surfaces

Cited by 27 publications

References 58 publications

Electrochemical interaction of Shewanella oneidensis MR-1 and its outer membrane cytochromes OmcA and MtrC with hematite electrodes

Electrochemical interaction of Shewanella oneidensis MR-1 and its outer membrane cytochromes OmcA and MtrC with hematite electrodes

Effects of Solution Chemistry and Aging Time on Prion Protein Adsorption and Replication of Soil-Bound Prions

Light Harvesting Proteins for Solar Fuel Generation in Bioengineered Photoelectrochemical Cells

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