Related Experiment Video
Updated: Aug 23, 2025
11:55
Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution
Published on: August 16, 2016
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Electrostatic Filtering of Polypeptides Through Membrane Protein Pores
Devika Vikraman1,2, Smrithi Krishnan R1,2, Remya Satheesan1,2
1Membrane Biology Laboratory, Transdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India.
Chemistry, an Asian Journal
|November 3, 2022
Summary
Naturally occurring CymA bacterial porins can detect single molecules. This study shows CymA selectively transports cationic polypeptides, highlighting its potential for nanopore proteomics.
Area of Science:
- Biochemistry
- Biophysics
- Molecular Biology
Background:
- Naturally occurring membrane proteins are engineered as nanopore sensors for single-molecule detection.
- Bacterial porins offer unique structural and charge features for molecular sensing.
Purpose of the Study:
- To investigate the translocation of charged polypeptides through the natural bacterial porin CymA.
- To elucidate the role of CymA's dynamic component and charged residues in molecular transport and binding.
Main Methods:
- Utilized single-channel recordings to monitor polypeptide translocation through native and truncated CymA.
- Investigated the binding affinity and translocation kinetics of cationic and anionic polypeptides under varying salt conditions.
Main Results:
- Cationic polypeptides exhibited high-affinity binding to CymA, dependent on electrostatic charge and voltage, particularly at low salt concentrations.
- Anionic peptides did not bind, confirming CymA's selective binding of cationic polypeptides.
- The dynamic segment of CymA was shown to play a crucial role in the kinetics of molecular transport.
Conclusions:
- CymA possesses selective translocation capabilities for cationic polypeptides.
- The dynamic component of CymA influences molecular transport kinetics.
- Engineered CymA porins show promise for nanopore proteomics applications due to their selective nature.
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