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Published on: April 16, 2018
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Redox Characterization of Electrode-Immobilized Bacterial Microcompartment Shell Proteins Engineered To Bind Metal
Jefferson S Plegaria, Matthew D Yates1, Sarah M Glaven1
1Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, D.C. 20375, United States.
ACS Applied Bio Materials
|January 12, 2022
Summary
Engineered bacterial microcompartment (BMC) shells can now coordinate copper ions. These modified protein shells exhibit reversible redox activity, paving the way for new biomolecular reactor designs.
Area of Science:
- Biochemistry
- Structural Biology
- Nanotechnology
Background:
- Bacterial microcompartments (BMC) are natural nanoscale protein shells that enhance metabolic efficiency by concentrating enzymes and substrates.
- Engineered BMC shells offer a versatile platform for creating artificial cellular compartments with tailored functions.
- Controlling the localization and activity of specific ions within BMCs is crucial for developing advanced biomolecular reactors.
Purpose of the Study:
- To engineer a BMC shell protein (BMC-T1HO) capable of coordinating copper (Cu) ions.
- To characterize the structural integrity and redox properties of the engineered Cu-coordinating BMC variants.
- To explore the potential of these engineered BMCs as electrode-bound redox-active architectures.
Main Methods:
- Design and synthesis of pseudohexameric/trimeric BMC-T1HO protein variants with strategically placed histidine residues for Cu coordination.
- Chemical denaturation experiments to assess the stability of the protein oligomerization state upon Cu binding.
- Electrochemical measurements (cyclic voltammetry) to determine the redox activity and formal potentials of electrode-bound Cu-BMC-T1HO variants.
Main Results:
- Several engineered BMC-T1HO variants maintained their trimeric structure after Cu coordination.
- Reversible redox activity was observed for electrode-bound Cu-3His BMC-T1HO variants.
- The formal redox potentials of the Cu ions were dependent on the specific coordination site within the BMC trimer, ranging from +208 to +265 mV vs SHE.
Conclusions:
- The study successfully engineered BMC shell proteins to coordinate Cu ions, demonstrating enhanced functionality.
- The engineered BMCs exhibit tunable redox properties when immobilized on electrode surfaces.
- These findings represent a significant advancement in developing functional and adaptable engineered BMC-based reactor systems.
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