title: Chemically tunable mucin chimeras assembled on living cells.
abstract: Mucins are a family of secreted and transmembrane glycoproteins characterized by a massive domain of dense O-glycosylation on serine and threonine residues. Mucins are intimately involved in immunity and cancer, yet elucidation of the biological roles of their glycodomains has been complicated by their massive size, domain polymorphisms, and variable glycosylation patterns. Here we developed a synthetic route to a library of compositionally defined, high-molecular weight, dual end-functionalized mucin glycodomain constructs via N-carboxyanhydride polymerization. These glycopolypeptides are the first synthetic analogs to our knowledge to feature the native α-GalNAc linkage to serine with molecular weights similar to native mucins, solving a nearly 50-year synthetic challenge. Physical characterization of the mimics revealed insights into the structure and properties of mucins. The synthetic glycodomains were end-functionalized with an optical probe and a tetrazine moiety, which allowed site-specific bioorthogonal conjugation to an engineered membrane protein on live mammalian cells. This strategy in protein engineering will open avenues to explore the biological roles of cell surface mucins.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305;
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Kramer
authors.affiliation: Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720;
authors.forename: Bibiana
authors.initials: B
authors.lastname: Onoa
authors.affiliation: Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720; Department of Chemistry, University of California, Berkeley, CA 94720; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; Department of Physics, University of California, Berkeley, CA 94720; Kavli Energy Nanosciences Institute at Berkeley, University of California, Berkeley, CA 94720; Howard Hughes Medical Institute, University of California, Berkeley, CA 94720;
authors.forename: Carlos
authors.initials: C
authors.lastname: Bustamante
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305 bertozzi@stanford.edu.
authors.forename: Carolyn R
authors.initials: CR
authors.lastname: Bertozzi
mesh_terms: D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D009077:Mucins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D009077:Mucins; D011993:Recombinant Fusion Proteins
keywords: N-carboxyanhydride; glycoprotein; mucin; polypeptide; protein engineering