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  3. Shotgun scanning glycomutagenesis: A simple and efficient strategy for constructing and characterizing neoglycoproteins

Shotgun scanning glycomutagenesis: A simple and efficient strategy for constructing and characterizing neoglycoproteins

  • Proc Natl Acad Sci U S A. 2021 Sep 28;118(39):e2107440118. doi: 10.1073/pnas.2107440118.
Mingji Li 1,  Xiaolu Zheng 1,  Sudhanshu Shanker 2,  Thapakorn Jaroentomeechai 1,  Tyler D Moeller 1,  Sophia W Hulbert 3,  Ilkay Koçer 1,  Josef Byrne 1,  Emily C Cox 4,  Qin Fu 5,  Sheng Zhang 5,  Jason W Labonte 2 6,  Jeffrey J Gray 7,  Matthew P DeLisa 8 3 4 5
Affiliations

Affiliations

  • 1 Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853.
  • 2 Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218.
  • 3 Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
  • 4 Biomedical and Biological Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.
  • 5 Cornell Institute of Biotechnology, Cornell University, Ithaca, NY 14853.
  • 6 Department of Chemistry, Franklin & Marshall College, Lancaster, PA 17604.
  • 7 Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218; jgray@jhu.edu md255@cornell.edu.
  • 8 Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853; jgray@jhu.edu md255@cornell.edu.
PMID: 34551980 DOI: 10.1073/pnas.2107440118
Abstract

As a common protein modification, asparagine-linked (N-linked) glycosylation has the capacity to greatly influence the biological and biophysical properties of proteins. However, the routine use of glycosylation as a strategy for engineering proteins with advantageous properties is limited by our inability to construct and screen large collections of glycoproteins for cataloguing the consequences of glycan installation. To address this challenge, we describe a combinatorial strategy termed shotgun scanning glycomutagenesis in which DNA libraries encoding all possible glycosylation site variants of a given protein are constructed and subsequently expressed in glycosylation-competent bacteria, thereby enabling rapid determination of glycosylatable sites in the protein. The resulting neoglycoproteins can be readily subjected to available high-throughput assays, making it possible to systematically investigate the structural and functional consequences of glycan conjugation along a protein backbone. The utility of this approach was demonstrated with three different acceptor proteins, namely Bacterial immunity protein Im7, bovine pancreatic ribonuclease A, and human anti-HER2 single-chain Fv antibody, all of which were found to tolerate N-glycan attachment at a large number of positions and with relatively high efficiency. The stability and activity of many glycovariants was measurably altered by N-linked glycans in a manner that critically depended on the precise location of the modification. Structural models suggested that affinity was improved by creating novel interfacial contacts with a glycan at the periphery of a protein-protein interface. Importantly, we anticipate that our glycomutagenesis workflow should provide access to unexplored regions of glycoprotein structural space and to custom-made neoglycoproteins with desirable properties.

Keywords

glycoengineering; glycosylation; protein design and engineering; synthetic biology.

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