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Expression system for structural and functional studies of human glycosylation enzymes

Abstract

Vertebrate glycoproteins and glycolipids are synthesized in complex biosynthetic pathways localized predominantly within membrane compartments of the secretory pathway. The enzymes that catalyze these reactions are exquisitely specific, yet few have been extensively characterized because of challenges associated with their recombinant expression as functional products. We used a modular approach to create an expression vector library encoding all known human glycosyltransferases, glycoside hydrolases, and sulfotransferases, as well as other glycan-modifying enzymes. We then expressed the enzymes as secreted catalytic domain fusion proteins in mammalian and insect cell hosts, purified and characterized a subset of the enzymes, and determined the structure of one enzyme, the sialyltransferase ST6GalNAcII. Many enzymes were produced at high yields and at similar levels in both hosts, but individual protein expression levels varied widely. This expression vector library will be a transformative resource for recombinant enzyme production, broadly enabling structure–function studies and expanding applications of these enzymes in glycochemistry and glycobiology.

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Figure 1: Flow chart for generation of glycoenzyme expression constructs.
Figure 2: Expression and secretion of the glycoenzyme constructs in mammalian cells.
Figure 3: Comparison of secreted enzyme expression in transfected mammalian cells and baculovirus-infected insect cells.
Figure 4: Structure of human ST6GalNAcII.

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References

  1. Moremen, K.W., Tiemeyer, M. & Nairn, A.V. Vertebrate protein glycosylation: diversity, synthesis and function. Nat. Rev. Mol. Cell Biol. 13, 448–462 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Varki, A. Biological roles of glycans. Glycobiology 27, 3–49 (2017).

    Article  CAS  PubMed  Google Scholar 

  3. National Research Council of the National Academies. Transforming Glycoscience: A Roadmap for the Future (National Academies Press, Washington DC, 2012).

  4. Nairn, A.V. & Moremen, K.W. in Handbook of Glycomics. (eds. R. Cummings & J.M. Pierce) 95–136 (Academic Press, Burlington, MA, 2009).

    Google Scholar 

  5. Cummings, R.D. The repertoire of glycan determinants in the human glycome. Mol. Biosyst. 5, 1087–1104 (2009).

    Article  CAS  PubMed  Google Scholar 

  6. Lombard, V., Golaconda Ramulu, H., Drula, E., Coutinho, P.M. & Henrissat, B. The carbohydrate-active enzymes database (CAZy) in 2013. Nucleic Acids Res. 42, D490–D495 (2014).

    Article  CAS  PubMed  Google Scholar 

  7. Lairson, L.L., Henrissat, B., Davies, G.J. & Withers, S.G. Glycosyltransferases: structures, functions, and mechanisms. Annu. Rev. Biochem. 77, 521–555 (2008).

    Article  CAS  PubMed  Google Scholar 

  8. Taniguchi, N. et al. Handbook of Glycosyltransferases and Related Genes, 2nd edn (Springer Tokyo, Japan, 2014).

  9. Rao, F.V. et al. Structural insight into mammalian sialyltransferases. Nat. Struct. Mol. Biol. 16, 1186–1188 (2009).

    Article  CAS  PubMed  Google Scholar 

  10. Seto, N.O., Palcic, M.M., Hindsgaul, O., Bundle, D.R. & Narang, S.A. Expression of a recombinant human glycosyltransferase from a synthetic gene and its utilization for synthesis of the human blood group B trisaccharide. Eur. J. Biochem. 234, 323–328 (1995).

    Article  CAS  PubMed  Google Scholar 

  11. Ramakrishnan, B. & Qasba, P.K. Crystal structure of lactose synthase reveals a large conformational change in its catalytic component, the beta1,4-galactosyltransferase-I. J. Mol. Biol. 310, 205–218 (2001).

    Article  CAS  PubMed  Google Scholar 

  12. Paulson, J.C. & Colley, K.J. Glycosyltransferases. Structure, localization, and control of cell type-specific glycosylation. J. Biol. Chem. 264, 17615–17618 (1989).

    CAS  PubMed  Google Scholar 

  13. Subedi, G.P., Johnson, R.W., Moniz, H.A., Moremen, K.W. & Barb, A. High yield expression of recombinant human proteins with the transient transfection of HEK293 cells in suspension. J. Vis. Exp. 106, e53568 (2015).

    Google Scholar 

  14. Jarvis, D.L. Recombinant protein expression in baculovirus-infected insect cells. Methods Enzymol. 536, 149–163 (2014).

    Article  CAS  PubMed  Google Scholar 

  15. Walhout, A.J. et al. GATEWAY recombinational cloning: application to the cloning of large numbers of open reading frames or ORFeomes. Methods Enzymol. 328, 575–592 (2000).

    Article  CAS  PubMed  Google Scholar 

  16. Stornaiuolo, M. et al. KDEL and KKXX retrieval signals appended to the same reporter protein determine different trafficking between endoplasmic reticulum, intermediate compartment, and Golgi complex. Mol. Biol. Cell 14, 889–902 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Carrington, J.C. & Dougherty, W.G. A viral cleavage site cassette: identification of amino acid sequences required for tobacco etch virus polyprotein processing. Proc. Natl. Acad. Sci. USA 85, 3391–3395 (1988).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Vandersall-Nairn, A.S., Merkle, R.K., O'Brien, K., Oeltmann, T.N. & Moremen, K.W. Cloning, expression, purification, and characterization of the acid alpha-mannosidase from Trypanosoma cruzi. Glycobiology 8, 1183–1194 (1998).

    Article  CAS  PubMed  Google Scholar 

  19. Schmidt, T.G. & Skerra, A. The Strep-tag system for one-step purification and high-affinity detection or capturing of proteins. Nat. Protoc. 2, 1528–1535 (2007).

    Article  CAS  PubMed  Google Scholar 

  20. Beckett, D., Kovaleva, E. & Schatz, P.J. A minimal peptide substrate in biotin holoenzyme synthetase-catalyzed biotinylation. Protein Sci. 8, 921–929 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Pédelacq, J.D., Cabantous, S., Tran, T., Terwilliger, T.C. & Waldo, G.S. Engineering and characterization of a superfolder green fluorescent protein. Nat. Biotechnol. 24, 79–88 (2006).

    Article  PubMed  Google Scholar 

  22. Barb, A.W. et al. NMR characterization of immunoglobulin G Fc glycan motion on enzymatic sialylation. Biochemistry 51, 4618–4626 (2012).

    Article  CAS  PubMed  Google Scholar 

  23. Reeves, P.J., Callewaert, N., Contreras, R. & Khorana, H.G. Structure and function in rhodopsin: high-level expression of rhodopsin with restricted and homogeneous N-glycosylation by a tetracycline-inducible N-acetylglucosaminyltransferase I-negative HEK293S stable mammalian cell line. Proc. Natl. Acad. Sci. USA 99, 13419–13424 (2002).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Meng, L. et al. Enzymatic basis for N-glycan sialylation: structure of rat α2,6-sialyltransferase (ST6GAL1) reveals conserved and unique features for glycan sialylation. J. Biol. Chem. 288, 34680–34698 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Kuhn, B. et al. The structure of human α-2,6-sialyltransferase reveals the binding mode of complex glycans. Acta Crystallogr. D Biol. Crystallogr. 69, 1826–1838 (2013).

    Article  CAS  PubMed  Google Scholar 

  26. Volkers, G. et al. Structure of human ST8SiaIII sialyltransferase provides insight into cell-surface polysialylation. Nat. Struct. Mol. Biol. 22, 627–635 (2015).

    Article  CAS  PubMed  Google Scholar 

  27. Datta, A.K. & Paulson, J.C. The sialyltransferase “sialylmotif” participates in binding the donor substrate CMP-NeuAc. J. Biol. Chem. 270, 1497–1500 (1995).

    Article  CAS  PubMed  Google Scholar 

  28. Livingston, B.D. & Paulson, J.C. Polymerase chain reaction cloning of a developmentally regulated member of the sialyltransferase gene family. J. Biol. Chem. 268, 11504–11507 (1993).

    CAS  PubMed  Google Scholar 

  29. Kellokumpu, S., Hassinen, A. & Glumoff, T. Glycosyltransferase complexes in eukaryotes: long-known, prevalent but still unrecognized. Cell. Mol. Life Sci. 73, 305–325 (2016).

    Article  CAS  PubMed  Google Scholar 

  30. Gleeson, P.A. Targeting of proteins to the Golgi apparatus. Histochem. Cell Biol. 109, 517–532 (1998).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  31. Revoredo, L. et al. Mucin-type O-glycosylation is controlled by short- and long-range glycopeptide substrate recognition that varies among members of the polypeptide GalNAc transferase family. Glycobiology 26, 360–376 (2016).

    Article  CAS  PubMed  Google Scholar 

  32. Halmo, S.M. et al. Protein O-linked mannose β-1,4-N-acetylglucosaminyl-transferase 2 (POMGNT2) Is a gatekeeper enzyme for functional glycosylation of α-dystroglycan. J. Biol. Chem. 292, 2101–2109 (2017).

    Article  CAS  PubMed  Google Scholar 

  33. Praissman, J.L. et al. The functional O-mannose glycan on α-dystroglycan contains a phospho-ribitol primed for matriglycan addition. eLife 5, e14473 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Gao, Y. et al. Acceptor specificities and selective inhibition of recombinant human Gal- and GlcNAc-transferases that synthesize core structures 1, 2, 3 and 4 of O-glycans. Biochim. Biophys. Acta 1830, 4274–4281 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Gerken, T.A. et al. The lectin domain of the polypeptide GalNAc transferase family of glycosyltransferases (ppGalNAc Ts) acts as a switch directing glycopeptide substrate glycosylation in an N- or C-terminal direction, further controlling mucin type O-glycosylation. J. Biol. Chem. 288, 19900–19914 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Sheikh, M.O. et al. Rapid screening of sugar-nucleotide donor specificities of putative glycosyltransferases. Glycobiology 27, 206–212 (2017).

    Article  CAS  PubMed  Google Scholar 

  37. Urbanowicz, B.R., Peña, M.J., Moniz, H.A., Moremen, K.W. & York, W.S. Two Arabidopsis proteins synthesize acetylated xylan in vitro. Plant J. 80, 197–206 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  38. Hanes, M.S., Moremen, K.W. & Cummings, R.D. Biochemical characterization of functional domains of the chaperone Cosmc. PLoS One 12, e0180242 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. Praissman, J.L. et al. B4GAT1 is the priming enzyme for the LARGE-dependent functional glycosylation of α-dystroglycan. eLife 3, e03943 (2014).

    Article  CAS  PubMed Central  Google Scholar 

  40. Li, T. et al. Divergent chemoenzymatic synthesis of asymmetrical-core-fucosylated and core-unmodified N-glycans. Chemistry 22, 18742–18746 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Bello, C., Wang, S., Meng, L., Moremen, K.W. & Becker, C.F. A PEGylated photocleavable auxiliary mediates the sequential enzymatic glycosylation and native chemical ligation of peptides. Angew. Chem. Int. Edn Engl. 54, 7711–7715 (2015).

    Article  CAS  Google Scholar 

  42. Prudden, A.R. et al. Synthesis of asymmetrical multiantennary human milk oligosaccharides. Proc. Natl. Acad. Sci. USA 114, 6954–6959 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Epp, A. et al. Sialylation of IgG antibodies inhibits IgG-mediated allergic reactions. J. Allergy Clin. Immunol. DOI:10.1016/j.jaci.2017.06.021

    Article  CAS  PubMed  Google Scholar 

  44. Mbua, N.E. et al. Selective exo-enzymatic labeling of N-glycans on the surface of living cells by recombinant ST6Gal I. Angew. Chem. Int. Edn Engl. 52, 13012–13015 (2013).

    Article  CAS  Google Scholar 

  45. Sun, T. et al. One-step selective exoenzymatic labeling (SEEL) strategy for the biotinylation and identification of glycoproteins of living cells. J. Am. Chem. Soc. 138, 11575–11582 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  46. Yu, S.H. et al. Selective exo-enzymatic labeling detects increased cell surface sialoglycoprotein expression upon megakaryocytic differentiation. J. Biol. Chem. 291, 3982–3989 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  47. Marcos, N.T. et al. Role of the human ST6GalNAc-I and ST6GalNAc-II in the synthesis of the cancer-associated sialyl-Tn antigen. Cancer Res. 64, 7050–7057 (2004).

    Article  CAS  PubMed  Google Scholar 

  48. Zhang, C. et al. Structural basis for regulation of human calcium-sensing receptor by magnesium ions and an unexpected tryptophan derivative co-agonist. Sci. Adv. 2, e1600241 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Urbanowicz, B.R. et al. Structural, mutagenic and in silico studies of xyloglucan fucosylation in Arabidopsis thaliana suggest a water-mediated mechanism. Plant J. 91, 931–949 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. The UniProt Consortium. UniProt: the universal protein knowledgebase. Nucleic Acids Res. 45, D158–D169 (2017).

  51. Gerhard, D.S. et al. The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome Res. 14, 2121–2127 (2004).

    Article  PubMed  Google Scholar 

  52. Tessier, D.C., Thomas, D.Y., Khouri, H.E., Laliberté, F. & Vernet, T. Enhanced secretion from insect cells of a foreign protein fused to the honeybee melittin signal peptide. Gene 98, 177–183 (1991).

    Article  CAS  PubMed  Google Scholar 

  53. Luft, J.R. et al. A deliberate approach to screening for initial crystallization conditions of biological macromolecules. J. Struct. Biol. 142, 170–179 (2003).

    Article  CAS  PubMed  Google Scholar 

  54. Otwinowski, Z. & Minor, W. Processing of X-ray diffraction data collected in oscillation mode. Methods Enzymol. 276, 307–326 (1997).

    Article  CAS  PubMed  Google Scholar 

  55. Sheldrick, G.M. A short history of SHELX. Acta Crystallogr. A 64, 112–122 (2008).

    Article  CAS  PubMed  Google Scholar 

  56. McRee, D.E. XtalView/Xfit--A versatile program for manipulating atomic coordinates and electron density. J. Struct. Biol. 125, 156–165 (1999).

    Article  CAS  PubMed  Google Scholar 

  57. Jogl, G., Tao, X., Xu, Y. & Tong, L. COMO: a program for combined molecular replacement. Acta Crystallogr. D Biol. Crystallogr. 57, 1127–1134 (2001).

    Article  CAS  PubMed  Google Scholar 

  58. Schröder, G.F., Levitt, M. & Brunger, A.T. Super-resolution biomolecular crystallography with low-resolution data. Nature 464, 1218–1222 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Adams, P.D. et al. PHENIX: a comprehensive Python-based system for macromolecular structure solution. Acta Crystallogr. D Biol. Crystallogr. 66, 213–221 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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Acknowledgements

We wish to thank F. Samli, R. Collins, L. Stanton, A. Petrey, A. Yox, R. Kim and J. Aumiller for technical assistance during these studies. This research was supported by NIH grants P41GM103390 (to K.W.M.), P01GM107012 (G.J. Boons, PI), P41GM103490 (J.M. Pierce, PI) and U54GM094597 for work performed in part as a community nominated project of the Protein Structure Initiative of the National Institutes of Health (to G.T. Montelione and L.T.).

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Authors and Affiliations

Authors

Contributions

K.W.M., D.L.J. and J.L. formulated the project; K.W.M. designed glycoenzyme truncation and fusion constructs and supervised mammalian cell expression efforts; D.L.J. supervised preparation of baculovirus constructs and insect cell expression efforts; A.V.N. generated all target mammalian glycogene lists including gene and protein annotations; J.L. and J. Steel designed primers and executed high-throughput glycogene amplification and Gateway recombination; A.R. and M.d.R. generated human cDNAs and mammalian expression vectors, and performed Gateway recombination into mammalian expression vectors; C.G. and G.G. generated all baculovirus DEST expression vectors, M.S. and G.G. performed Gateway recombination into baculovirus expression vectors, screened and amplified viral stocks, and characterized recombinant protein expression in insect cells, H.A.M., Z.G., D.C., S.W., J.-Y.Y., L.M., P.K.P., and R.J. characterized expression of glycoenzymes in mammalian cells; C.G. designed baculovirus DEST expression vectors; S.-C.W. and H.J.G. designed and generated fusion protein constructs for expression in bacteria. L.M. expressed and purified recombinant ST6GalNAcII for structural studies. F.F., J. Seetharaman, and L.T. performed structural studies on ST6GalNAcII.

Corresponding authors

Correspondence to Kelley W Moremen or Donald L Jarvis.

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Competing interests

D.L.J. is the President and C.G. is now an employee of GlycoBac, LLC, a biotechnology spinout that focuses on insect host cell improvements, but that could conceivably profit from the results described herein.

Supplementary information

Supplementary Text and Figures

Supplementary Tables 1–3 and Supplementary Figures 1–10 (PDF 1623 kb)

Life Sciences Reporting Summary (PDF 130 kb)

Supplementary Data Set 1

Summary of human glycosylation enzyme fusion protein expression strategies and expression results for production in HEK293 cells and BEVS (XLSX 186 kb)

Supplementary Data Set 2

DNA sequences of human glycosylation enzyme expression constructs (XLSX 312 kb)

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Moremen, K., Ramiah, A., Stuart, M. et al. Expression system for structural and functional studies of human glycosylation enzymes. Nat Chem Biol 14, 156–162 (2018). https://doi.org/10.1038/nchembio.2539

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