Chemically tunable mucin chimeras assembled on living cells

Area of Science:

• Glycobiology
• Polymer Chemistry
• Biochemistry

Background:

• Mucins are complex glycoproteins crucial in immunity and cancer.
• Studying mucin glycodomains is challenging due to their size, polymorphisms, and glycosylation variability.
• Understanding mucin structure-function relationships is vital for therapeutic development.

Purpose of the Study:

• To develop synthetic analogs of mucin glycodomains.
• To create compositionally defined, high-molecular weight mucin glycodomain constructs.
• To enable site-specific bioorthogonal conjugation for studying cell surface mucins.

Main Methods:

• N-carboxyanhydride polymerization was used to synthesize dual end-functionalized glycopolypeptides.
• The synthetic constructs mimic native mucins' molecular weight and feature native α-GalNAc linkages.
• Bioorthogonal conjugation was achieved using an optical probe and tetrazine moiety on engineered membrane proteins.

Main Results:

• A synthetic route was established for high-molecular weight, dual end-functionalized mucin glycodomain constructs.
• The synthetic glycopolypeptides are the first to replicate native α-GalNAc linkage to serine with native mucin-like molecular weights.
• Physical characterization provided new insights into mucin structure and properties.
• Successful site-specific bioorthogonal conjugation to live mammalian cells was demonstrated.

Conclusions:

• This work presents a significant advancement in synthesizing mucin glycodomain mimics.
• The synthetic strategy overcomes a long-standing synthetic challenge in glycobiology.
• This approach facilitates the exploration of cell surface mucin functions in biological systems.
• The developed methodology opens new avenues for protein engineering and therapeutic research.