Dissecting Bioelectrical Networks in Photosynthetic Membranes with Electrochemistry

Area of Science:

• Biochemistry
• Bioenergetics
• Electrochemistry

Background:

• Photosynthetic membranes possess intricate redox networks crucial for life's energy conversion.
• Studying these networks in native membrane environments is challenging due to complexity and limited electrochemical accessibility.
• Existing methods struggle to probe electron transfer at a systems-level within intact membranes.

Purpose of the Study:

• To develop and demonstrate an electrochemical method for analyzing electron transfer networks in native photosynthetic membranes.
• To investigate the interplay between different redox pathways and components within these membranes.
• To explore the potential of this method for biotechnological applications.

Main Methods:

• Wiring native cyanobacterial photosynthetic membranes to electrodes using structured electrodes.
• Utilizing electrochemistry to measure electron transfer signatures at the protein and pathway levels.
• Performing in operando spectroscopic measurements for validation.
• Extracting electrons from native membrane-bound Photosystem I.

Main Results:

• Distinct electrochemical signatures were observed from native membranes, enabling systems-level analysis.
• Overlapping photosynthetic and respiratory pathways, along with quinone redox activity, were characterized.
• Electrons were successfully extracted from native membrane-bound Photosystem I at -600 mV versus SHE, a significantly lower potential than for purified photosystems.
• The method provides insights into the interplay of redox components within the native membrane.

Conclusions:

• The developed electrochemical approach effectively probes complex electron transfer networks in native photosynthetic membranes.
• This technique offers a powerful tool for understanding biological energy conversion and developing new biotechnologies.
• The ability to access low redox potentials from native Photosystem I opens new avenues for solar energy and biocatalysis.