Electron Transfer Proteins

Warren, Jeffrey J.; Gray, Harry B.

doi:10.1016/b978-0-12-409547-2.14831-0

Cited by 3 publications

(2 citation statements)

References 221 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To satisfy this demand, close contact of the enzyme with the electrode surface must be ensured. The well-known general way to enhance the effectiveness of ET is the application of electroactive mediators—freely diffusing or/and immobilized ones coupled with the enzyme on the surface of the electrode [ 50 ].…”

Section: Resultsmentioning

confidence: 99%

Flavocytochrome b2-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors

et al. 2023

View full text Add to dashboard Cite

L-Lactate is an indicator of food quality, so its monitoring is essential. Enzymes of L-Lactate metabolism are promising tools for this aim. We describe here some highly sensitive biosensors for L-Lactate determination which were developed using flavocytochrome b2 (Fcb2) as a bio-recognition element, and electroactive nanoparticles (NPs) for enzyme immobilization. The enzyme was isolated from cells of the thermotolerant yeast Ogataea polymorpha. The possibility of direct electron transfer from the reduced form of Fcb2 to graphite electrodes has been confirmed, and the amplification of the electrochemical communication between the immobilized Fcb2 and the electrode surface was demonstrated to be achieved using redox nanomediators, both bound and freely diffusing. The fabricated biosensors exhibited high sensitivity (up to 1436 A·M−1·m−2), fast responses, and low limits of detection. One of the most effective biosensors, which contained co-immobilized Fcb2 and the hexacyanoferrate of gold, having a sensitivity of 253 A·M−1·m−2 without freely diffusing redox mediators, was used for L-Lactate analysis in samples of yogurts. A high correlation was observed between the values of analyte content determined using the biosensor and referenced enzymatic-chemical photometric methods. The developed biosensors based on Fcb2-mediated electroactive nanoparticles can be promising for applications in laboratories of food control.

show abstract

Section: Resultsmentioning

confidence: 99%

Flavocytochrome b2-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Whether these systems are flexible enough to allow R e < R * remains an open question. Azurin itself is viewed as an exceptionally stable and rigid protein 104 raising the question of whether lifting the level of the distance-independent plateau in Figure 6 through rigidity is a general principle of operation for charge-transfer proteins.…”

Section: Discussionmentioning

confidence: 99%

Electron Tunneling in Biology: When Does it Matter?

Sarhangi

Matyushov

2023

ACS Omega

View full text Add to dashboard Cite

Electrons can tunnel between cofactor molecules positioned along biological electron transport chains up to a distance of ≃ 20 Å on the millisecond time scale of enzymatic turnover. This tunneling range determines the design of biological energy chains facilitating the cross-membrane transport of electrons. Tunneling distance and cofactors’ redox potentials become the main physical parameters affecting the rate of electron transport. In addition, universal charge-transport properties are assigned to all proteins, making protein identity, flexibility, and dynamics insignificant. This paradigm is challenged by dynamical models of electron transfer, showing that the electron hopping rate is constant within the crossover distance R* ≃ 12 Å, followed with an exponential falloff at longer distances. If this hypothesis is fully confirmed, natural and man-made energy chains for electron transport should be best designed by placing redox cofactors near the crossover distance R*. Protein flexibility and dynamics affect the magnitude of the maximum hopping rate within the crossover distance. Changes in protein flexibility between forward and backward transitions contribute to vectorial charge transport. For biological energy chains, charge transport through proteins is not defined by universal parameters, and protein identity matters.

show abstract

Nanosecond heme-to-heme electron transfer rates in a multiheme cytochrome nanowire reported by a spectrally unique His/Met-ligated heme

Wonderen

Adamczyk

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Proteins achieve efficient energy storage and conversion through electron transfer along a series of redox cofactors. Multiheme cytochromes are notable examples. These proteins transfer electrons over distance scales of several nanometers to >10 μm and in so doing they couple cellular metabolism with extracellular redox partners including electrodes. Here, we report pump-probe spectroscopy that provides a direct measure of the intrinsic rates of heme–heme electron transfer in this fascinating class of proteins. Our study took advantage of a spectrally unique His/Met-ligated heme introduced at a defined site within the decaheme extracellular MtrC protein of Shewanella oneidensis. We observed rates of heme-to-heme electron transfer on the order of 109 s−1 (3.7 to 4.3 Å edge-to-edge distance), in good agreement with predictions based on density functional and molecular dynamics calculations. These rates are among the highest reported for ground-state electron transfer in biology. Yet, some fall 2 to 3 orders of magnitude below the Moser–Dutton ruler because electron transfer at these short distances is through space and therefore associated with a higher tunneling barrier than the through-protein tunneling scenario that is usual at longer distances. Moreover, we show that the His/Met-ligated heme creates an electron sink that stabilizes the charge separated state on the 100-μs time scale. This feature could be exploited in future designs of multiheme cytochromes as components of versatile photosynthetic biohybrid assemblies.

show abstract

Electron Transfer Proteins

Cited by 3 publications

References 221 publications

Flavocytochrome b2-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors

Flavocytochrome b2-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors

Electron Tunneling in Biology: When Does it Matter?

Nanosecond heme-to-heme electron transfer rates in a multiheme cytochrome nanowire reported by a spectrally unique His/Met-ligated heme

Contact Info

Product

Resources

About