Programming N-linked glycan composition through de novo protein design

N-linked glycans are crucial post-translational modifications involved in various biological functions such as cell signaling, adhesion, molecular recognition, and host-pathogen interactions. However, designing N-linked glycans using biomolecular methods has been challenging due to the absence of tools that can simultaneously model glycans and protein structures.

In this study, researchers have developed a comprehensive computational pipeline for designing de novo glycoproteins. This innovative approach allows the amino acid sequence to encode both the location and composition of N-linked glycans. The method utilizes three-dimensional protein structure to regulate glycan accessibility to processing enzymes within the eukaryotic secretory pathway.

By increasing steric restriction systematically, the processing of glycans decreases, leading to a shift from complex-type structures to more underprocessed oligomannose-type species, similar to those found on many viral glycoproteins.

Despite the programmed restriction, the resulting oligomannose glycans remain accessible for biological recognition. This finding demonstrates that the inhibition of uropathogenic Escherichia coli adhesion to human bladder cells and binding of mannose-binding lectin is possible. These results establish steric control of N-glycan processing as a genetically encodable design principle and expand computational protein design to include functional glycoproteins with predetermined composition.