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Sensing PEGylated Peptide Conformations Using a Protein Nanopore
Remya Satheesan1,2, Devika Vikraman1,2, Parvathy Jayan3
1Membrane Biology Laboratory, Transdisciplinary Biology Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India.
Nano Letters
|February 5, 2024
Summary
This study explores how different sizes of polyethylene glycol (PEG)-tagged peptides interact with the CymA protein pore using electrical recordings. Larger PEG peptides show varied conformations, while smaller ones translocate, enabling specific sensing applications in proteomics.
Area of Science:
- Biophysics
- Nanotechnology
- Analytical Chemistry
Background:
- Membrane pores are utilized for stochastic sensing of analytes.
- Protein pores, like CymA, offer unique channels for molecular interactions.
Purpose of the Study:
- To investigate the interaction of PEGylated peptides of varying sizes with the CymA protein pore.
- To explore the potential of CymA pore for sensing peptide size and conformation.
Main Methods:
- Electrical recordings of single-channel currents.
- Electrophoretic binding of polyethylene glycol (PEG)-tagged peptides to the CymA pore.
- Analysis of blockage events and translocation dynamics.
Main Results:
- Small PEGylated peptides (PEG 200) showed voltage-dependent translocation and monodisperse blockages.
- Larger PEGylated peptides (PEG 1000, 2000) exhibited heterogeneous blockages due to diverse conformations.
- Very large PEGylated peptides (PEG 5000) completely occluded the pore.
- Competitive binding experiments demonstrated specific blockage signals based on peptide identity, size, and conformation.
Conclusions:
- The CymA pore can differentiate between PEGylated peptides based on size and conformation.
- The sensing mechanism relates to disordered protein unfolding, applicable to proteomics.
- This system holds promise for developing novel biosensors for complex molecules.
