30.01.2025
Self-assembled poly(C9) nanopores enable protein shape & volume analysis
Biological nanopores are powerful tools for single-molecule analysis. However, existing nanopore technologies often struggle to accurately analyze large, folded proteins due to limitations in pore size and stability.
A recent study introduces a novel biological nanopore system based on complement component 9 (C9), a protein that plays a key role in the immune system’s membrane attack complex (MAC). In its native function, C9 assembles with other complement proteins to form pores in bacterial membranes. In this study, researchers leveraged C9’s self-assembling properties to create large, stable nanopores (poly(C9)) with a diameter of 10 ± 4 nm and a length of 13 nm. These poly(C9) nanopores remain stable across a wide range of conditions, allowing for detailed single-molecule analysis of proteins.
Using an advanced planar lipid bilayer recording system, the Orbit mini, the study demonstrated that poly(C9) nanopores could precisely estimate both the volume (space occupied) and shape (ratio of length to diameter) of individual proteins. The method successfully characterized proteins ranging in molecular weight from 9 to 230 kDa, with precise shape estimations distinguishing between elongated (prolate) and more compact (oblate) structures.
Notably, poly(C9) nanopores could differentiate between different conformations of the same protein, as shown with adenylate kinase, an enzyme that switches between an open and closed state.
These findings establish poly(C9) nanopores as a highly accurate tool for single-protein analysis, providing new insights into protein folding, conformational dynamics, and molecular interactions.
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Find the full article here: Large and Stable Nanopores Formed by Complement Component 9 for Characterizing Single Folded Proteins
Learn more about parallel lipid bilayer recordings: https://www.nanion.de/products/orbit-mini/