Apparent redistribution of electron flow between redox cofactors branches in photosystem I from the menB variants of cyanobacterium Synechocystis sp. PCC 6803.

Interruption of menB gene in cyanobacterium Synechocystis sp. PCC 6803 causes a redistribution of electron flow in photosystem I, favoring the B-branch over the A-branch.

• Why it matters: Understanding how genetic modifications affect electron transfer pathways in photosystem I can reveal mechanisms of photosynthetic regulation and adaptation, which are crucial for bioengineering and improving photosynthetic efficiency.
• What they did: Researchers analyzed PS I from two menB variants with either loosely or tightly bound plastoquinone-9, using flash-induced optical changes and direct electrometry to characterize electron transfer kinetics and membrane potential generation.
• The result: The study found a functional predominance of electron transfer along the B-branch in menB variants, likely due to vacancy at the A 1A site, indicating a redistribution of electron flow that aligns with theoretical models of slowed electron transfer.