Evolutionary Relationships Between Low Potential Ferredoxin and Flavodoxin Electron Carriers.

Area of Science:

• Biochemistry and Molecular Biology
• Bioinformatics
• Evolutionary Biology

Background:

• Ferredoxins (Fd) and flavodoxins (Fld) are crucial low-potential electron transfer proteins.
• These proteins mediate electron transfer between various oxidoreductases.
• Understanding their distribution is key to comprehending cellular electron transport.

Purpose of the Study:

• To analyze the distribution of ferredoxin and flavodoxin genes across diverse organisms.
• To investigate the evolutionary patterns of small protein electron carrier (PEC) gene usage.
• To identify trends in PEC gene families across Archaea, Bacteria, and Eukarya.

Main Methods:

• Bioinformatic analysis of over 7,000 genomes.
• Focused on genes encoding small PECs (≤200 residues).
• Mapped PEC gene distribution onto an evolutionary tree.

Main Results:

• Average small PEC gene counts vary: Archaea (~13), Bacteria (~8), Eukarya (~3).
• Organisms are categorized into PEC-lacking (3%), specialists (20%), and generalists (77%).
• [4Fe-4S] Fds are prevalent in ancient organisms; [2Fe-2S] Fds expanded with photosynthesis; Flds expanded in low-iron environments.

Conclusions:

• Protein electron carrier gene usage is highly diverse across life.
• Evolutionary pressures, such as photosynthesis and host environment, shape PEC gene families.
• Further research into understudied PECs' structure, stability, and function is warranted.