Energetic insights into two electron transfer pathways in light-driven energy-converting enzymes

Kawashima, Keisuke; Ishikita, Hiroshi

doi:10.1039/c8sc00424b

Cited by 44 publications

(101 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…is not relevant as a charge-separated intermediate (19). This is in line with the proposal that Chl D1…”

Section: •-supporting

confidence: 91%

“…•formation, and thus decrease E m (B M ) ( Fig. 3A) (19). It is characteristic to PbRC that polar, uncharged residues stabilize B L…”

Section: Resultsmentioning

confidence: 93%

“…formation (19). The factors that increase E m (B L ) 0/•with respect to E m (B M ) 0/•are 1) the difference in the polarity of the uncharged L/M residue pairs in the hydrophobic transmembrane region [e.g., Phe-L181/Tyr-M210 (19,20)], 2) acidic residues that provide the binding interface of cytochrome c 2 on the protein surface of subunit M [e.g., Glu-M95 and Asp-M184 (19,21)], and 3) a cluster of hydrophobic residues that form the carotenoid binding site (19). In contrast to PbRC, E m (Chl D1 ) 0/•is lower than E m (Chl D2 ) 0/•in PSII, which suggests that Chl D1…”

Section: •-mentioning

confidence: 99%

“…•+ are involved in the Mn 4 CaO 5 cluster or the proceeding proton transfer pathway (e.g., D1-Asp61/ D2-His61, D1-Asp170/D2-Phe169, D1-Asn181/D2-Arg180, and D1-Glu189/D2-Phe188) (19). The absence of the corresponding residues in PbRC implies that the energetic difference between…”

Section: •-mentioning

confidence: 99%

See 3 more Smart Citations

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Tamura

Saito

Ishikita

2020

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

Self Cite

View full text Add to dashboard Cite

In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron–hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochromec2binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1•+and is stabilized predominantly by charged residues near the Mn4CaO5cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1the initial electron donor in PSII.

show abstract

“…is not relevant as a charge-separated intermediate (19). This is in line with the proposal that Chl D1…”

Section: •-supporting

confidence: 91%

“…•formation, and thus decrease E m (B M ) ( Fig. 3A) (19). It is characteristic to PbRC that polar, uncharged residues stabilize B L…”

Section: Resultsmentioning

confidence: 93%

Section: •-mentioning

confidence: 99%

Section: •-mentioning

confidence: 99%

See 2 more Smart Citations

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Tamura

Saito

Ishikita

2020

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…11 The atomic charges of the other cofactors in the MM region were taken from a previous study. 27 E m calculations for the electron transfer pathway via TyrZÁ Á ÁD1-His190…”

Section: Methodsmentioning

confidence: 99%

Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

Saito

Mandal

Ishikita

2020

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

Bioinspired Self‐Assembly of Metalloporphyrins and Polyelectrolytes into Hierarchical Supramolecular Nanostructures for Enhanced Photocatalytic H₂ Production in Water

Tang,

Han,

Chen

et al. 2024

Angewandte Chemie

View full text Add to dashboard Cite

Polypeptides, as natural polyelectrolytes, are assembled into tailored proteins to integrate chromophores and catalytic sites for photosynthesis. Mimicking nature to create the water‐soluble nanoassemblies from synthetic polyelectrolytes and photocatalytic molecular species for artificial photosynthesis is still rare. Here, we report the enhancement of the full‐spectrum solar light‐driven H2 production within a supramolecular system built by the co‐assembly of anionic metalloporphyrins with cationic polyelectrolytes in water. This supramolecular photocatalytic system achieves a H2 production rate of 793 and 685 μmol h‐1 g‐1 over 24 h with a combination of Mg or Zn porphyrin as photosensitizers and Cu porphyrin as catalyst, which is more than 23 times higher than that of free molecular controls. With a photosensitizer to catalyst ratio of 10000:1, the highest H2 production rate of > 51,700 μmol h‐1 g‐1 with a turnover number (TON) of > 1,290 per molecular catalyst was achieved over 24 h irradiation. The hierarchical self‐assembly not only enhances photostability via forming ordered stackings of the metalloporphyrins but also facilitates both energy and electron transfer from antenna molecules to catalysts, and therefore promote the photocatalysis. This research provides structural and mechanistic insights of self‐assembly enhanced photostability and catalytic performance of supramolecular photocatalytic systems.

show abstract

Energetic insights into two electron transfer pathways in light-driven energy-converting enzymes

Abstract: We report Em values of (bacterio-)chlorophylls for one-electron reduction in both electron-transfer branches of PbRC, PSI, and PSII.

Cited by 44 publications

References 60 publications

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

Bioinspired Self‐Assembly of Metalloporphyrins and Polyelectrolytes into Hierarchical Supramolecular Nanostructures for Enhanced Photocatalytic H₂ Production in Water

Contact Info

Product

Resources

About

Energetic insights into two electron transfer pathways in light-driven energy-converting enzymes

Abstract: We report Em values of (bacterio-)chlorophylls for one-electron reduction in both electron-transfer branches of PbRC, PSI, and PSII.

Cited by 44 publications

References 60 publications

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

Bioinspired Self‐Assembly of Metalloporphyrins and Polyelectrolytes into Hierarchical Supramolecular Nanostructures for Enhanced Photocatalytic H2 Production in Water

Contact Info

Product

Resources

About

Bioinspired Self‐Assembly of Metalloporphyrins and Polyelectrolytes into Hierarchical Supramolecular Nanostructures for Enhanced Photocatalytic H₂ Production in Water