Protein nanopores are found in cell membranes and serve as biological gateways. This means that they can also be used for detecting specific bioactive molecular chains, like sugar chains, such as molecules from the glycosaminoglycan group. The latter are responsible for crucial cellular level interactions. They usually facilitate interactions with cell surfaces or with proteins, triggering the activation of pathological and physiological effects in embryonic development, inflammatory response, cell growth and differentiation, microbial infection, and tumor growth.
The use of such nanopores as biosensors is required to fully comprehend the complex mechanisms taking place as sugar chains pass through them. In a new research reported in EPJ E, Aziz Fennouri from Paris-Saclay University in Evry, France, and colleagues outline the core criteria establishing the efficiency of two types of nanopores in the detecting sugar chains.
The researchers specifically investigate how two 10 nanometer-wide protein nanopores—namely α-hemolysin (α-HL) from Staphylococcus aureus and aerolysin (AeL) from Aeromonas hydrophila—influence the ability of sugar chain components of large biomolecules, such as hyaluronic acid to pass through the nanopores.
The researchers learned that, when the sugar chains enter from the wide end of the funnel constituting each pore, AeL can be used to sense short sugar chains. On the other hand, α-HL fails to sense such short chains because they cross the nanopore very rapidly. The opposite takes place when sugar chains are positioned at the thin end of the funnel-shaped pore.
These results reveal that the choice of the nanopore used to perform biosensing experiments is vital. Criteria other than the pore’s inner diameter need to be taken into consideration when devising biosensors to make then ideal for detection. Other parameters to deliberate upon include the charge repartition within the pore, the geometry of the pore channel, and possible interactions taking place on the inner wall of the pore channel.