Glycans play crucial roles in various cellular activities and have complex structures, making their structural analysis challenging. However, a recent breakthrough by a research team led by Prof. Qing Guangyan and Prof. Liang Xinmiao from the Dalian Institute of Chemical Physics has developed a glycan identification method using nanopore single-molecule sensing and a glycan derivatization strategy. This groundbreaking study, published in Nature Communications, overcomes previous limitations and opens up possibilities for glycan sequencing using nanopore technology.
Previous attempts at identifying and sequencing glycans using nanopore techniques were limited to high molecular weight polysaccharides or specific monosaccharides. Smaller glycans with greater structural diversity and biological significance remained difficult to analyze due to their fast passage through the nanopores, which couldn’t be adequately sensed due to their small size and weak affinity with the nanopore.
To tackle this challenge, the researchers employed a derivatization strategy, attaching an aromatic-type tag group to small glycans through a highly efficient reductive amination reaction. This tagging enabled the detection of the glycans using a wild-type aerolysin nanopore, resulting in strong nanopore blockage signals.
By analyzing the nanopore single-molecule blockage events, the researchers created a scatter plot based on blockage current and dwell time, which served as a fingerprint map for identifying different glycan isomers, glycans with varying lengths, and branched simple glycans.
Furthermore, the study revealed that multiple cation-π interactions between the aromatic tag of the glycan and specific residues of the nanopore interface played a crucial role in slowing down the translocation of the tagged glycan and contributed to the sensing process.
The successful application of nanopore sensing in glycomics and glycoscience expands the capabilities of this technology beyond its traditional focus on nucleic acids and proteins. Prof. Qing expressed optimism that this study could pave the way for nanopore glycan sequencing, further advancing research in this field.
Source: Chinese Academy of Sciences