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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Energy Res. | doi: 10.3389/fenrg.2019.00079

Evolutionary relationships between low potential ferredoxin and flavodoxin electron carriers

  • 1Biochemistry and Cell Biology Graduate Program, Department of BioSciences, Rice University, United States
  • 2Department of BioSciences, Rice University, United States
  • 3Department of Chemical and Biomolecular Engineering
, George R. Brown School of Engineering, Rice University, United States
  • 4Department of Bioengineering, George R. Brown School of Engineering, Rice University, United States

Proteins from the ferredoxin (Fd) and flavodoxin (Fld) families function as low potential electrical transfer hubs in cells, at times mediating electron transfer between overlapping sets of oxidoreductases. To better understand protein electron carrier (PEC) use across the domains of life, we evaluated the distribution of genes encoding [4Fe-4S] Fd, [2Fe-2S] Fd, and Fld electron carriers in over seven thousand organisms. Our analysis targeted genes encoding small PEC genes encoding proteins having ≤200 residues. We find that the average number of small PEC genes per Archaea (~13), Bacteria (~8), and Eukarya (~3) genome varies, with some organisms containing as many as 54 total PEC genes. Organisms fall into three groups, including those lacking genes encoding low potential PECs (3%), specialists with a single PEC gene type (20%), and generalists that utilize multiple PEC types (77%). Mapping PEC gene usage onto an evolutionary tree highlights the prevalence of [4Fe-4S] Fds in ancient organisms that are deeply rooted, the expansion of [2Fe-2S] Fds with the advent of photosynthesis and a concomitant decrease in [4Fe-4S] Fds, and the expansion of Flds in organisms that inhabit low-iron host environments. Surprisingly, [4Fe-4S] Fds present a similar abundance in aerobes as [2Fe-2S] Fds. This bioinformatic study highlights understudied PECs whose structure, stability, and partner specificity should be further characterized.

Keywords: Electron Transfer, evolution, Ferredoxin, Flavin Mononucleotide, Flavodoxin, iron-sulfur cluster, oxidoreductase, Oxidative Stress

Received: 03 Jun 2019; Accepted: 25 Jul 2019.

Copyright: © 2019 Campbell, Bennett and Silberg. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Jonathan J. Silberg, Department of BioSciences, Rice University, Houston, 77251-1892, Texas, United States, joff@rice.edu