Controlling the topology of polymer-modified proteins has attracted growing interest. However, one of the main challenges in this field is the lack of efficient and site-specific methods for installing multiple bioorthogonal functionalities on substrate polymers. We report here an orchestrating strategy that provides easy access to various topological protein-poly(amino acid) (PAA) conjugates in high yields. This method features the <i>in situ</i> installation of two “chemical handles”, including a thioester for native chemical ligation and a polyglycine tag for sortase A-mediated ligation, at both ends of substrate PAAs. As a result, neither pre-functionalization of initiator or monomer units, nor post-polymerization modification of the resultant polymers, is necessary. Site-specific topological conjugates, particularly circular conjugates, can be conveniently synthesized under mild conditions from the functionalized PAAs. The biomedical utility of our method is demonstrated by the rapid and efficient generation of several therapeutic interferon-α conjugates, which exhibited significantly enhanced protease resistance and thermostability. Given the versatility of both PAAs and proteins, the method offers a convenient approach producing libraries of conjugates for biological applications.

Synthesis and biomedical application of circular protein-poly(amino acid) conjugates

254th National Meeting (2017)

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