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Article
Cluster-Dependent Charge-Transfer Dynamics in Iron-Sulfur Proteins.
Biochemistry
  • Ziliang Mao
  • Shu-Hao Liou
  • Nimesh Khadka
  • Francis Jenney, Philadelphia College of Osteopathic Medicine
  • David B Goodin
  • Lance C Seefeldt
  • Michael W W Adams
  • Stephen P Cramer
  • Delmar S Larsen
Document Type
Article
Publication Date
1-24-2018
Abstract

Photoinduced charge-transfer dynamics and the influence of cluster size on the dynamics were investigated using five iron-sulfur clusters: the 1Fe-4S cluster in Pyrococcus furiosus rubredoxin, the 2Fe-2S cluster in Pseudomonas putida putidaredoxin, the 4Fe-4S cluster in nitrogenase iron protein, and the 8Fe-7S P-cluster and the 7Fe-9S-1Mo FeMo cofactor in nitrogenase MoFe protein. Laser excitation promotes the iron-sulfur clusters to excited electronic states that relax to lower states. The electronic relaxation lifetimes of the 1Fe-4S, 8Fe-7S, and 7Fe-9S-1Mo clusters are on the picosecond time scale, although the dynamics of the MoFe protein is a mixture of the dynamics of the latter two clusters. The lifetimes of the 2Fe-2S and 4Fe-4S clusters, however, extend to several nanoseconds. A competition between reorganization energies and the density of electronic states (thus electronic coupling between states) mediates the charge-transfer lifetimes, with the 2Fe-2S cluster of Pdx and the 4Fe-4S cluster of Fe protein lying at the optimum leading to them having significantly longer lifetimes. Their long lifetimes make them the optimal candidates for long-range electron transfer and as external photosensitizers for other photoactivated chemical reactions like solar hydrogen production. Potential electron-transfer and hole-transfer pathways that possibly facilitate these charge transfers are proposed.

PubMed ID
29303562
Comments

This article was published in Biochemistry.

The published version is available at https://doi.org/10.1021/acs.biochem.7b01159.

Copyright © 2018.

Citation Information
Ziliang Mao, Shu-Hao Liou, Nimesh Khadka, Francis Jenney, et al.. "Cluster-Dependent Charge-Transfer Dynamics in Iron-Sulfur Proteins." Biochemistry (2018)
Available at: http://works.bepress.com/francis_jenney/81/