Kinetics of trifurcated electron flow in the decaheme bacterial proteins MtrC and MtrF

Certain bacteria survive in anoxic environments by switching from aerobic to anaerobic respiration: in place of O2" role="presentation" id="MathJax-Element-1-Frame">O2, they reduce diverse substrates outside the cell. Multiheme cytochromes spanning the outer membrane have been identified as the essential building blocks for this process.

This study from Jochen Blumberger’s group, published in PNAS reveals that electron hopping through these proteins is strongly enhanced by cysteines at heme junctions that trifurcate the electron flow. They believe this to be a general design principle in multiheme cytochromes for acceleration of electron transfer (ET) steps that would otherwise be too slow for respiration. The study uncovers a natural design principle of significance to an entire class of proteins involved in biological ET.

https://www.pnas.org/content/116/9/3425

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