Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

A minimized human insulin-receptor-binding motif revealed in a Conus geographus venom insulin

Abstract

Insulins in the venom of certain fish-hunting cone snails facilitate prey capture by rapidly inducing hypoglycemic shock. One such insulin, Conus geographus G1 (Con-Ins G1), is the smallest known insulin found in nature and lacks the C-terminal segment of the B chain that, in human insulin, mediates engagement of the insulin receptor and assembly of the hormone's hexameric storage form. Removal of this segment (residues B23–B30) in human insulin results in substantial loss of receptor affinity. Here, we found that Con-Ins G1 is monomeric, strongly binds the human insulin receptor and activates receptor signaling. Con-Ins G1 thus is a naturally occurring B-chain-minimized mimetic of human insulin. Our crystal structure of Con-Ins G1 reveals a tertiary structure highly similar to that of human insulin and indicates how Con-Ins G1's lack of an equivalent to the key receptor-engaging residue PheB24 is mitigated. These findings may facilitate efforts to design ultrarapid-acting therapeutic insulins.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Characterization of Con-Ins G1.
Figure 2: Three-dimensional structure of Con-Ins G1.
Figure 3: Molecular model of Con-Ins G1 in the context of the primary insulin-binding site of the human insulin receptor.
Figure 4: Detail of Con-Ins G1 residues proposed to interact with the primary binding site of hIR.

Similar content being viewed by others

Accession codes

Primary accessions

Protein Data Bank

Referenced accessions

Protein Data Bank

References

  1. King, G.F. Venoms as a platform for human drugs: translating toxins into therapeutics. Expert Opin. Biol. Ther. 11, 1469–1484 (2011).

    Article  CAS  Google Scholar 

  2. Zambelli, V.O., Pasqualoto, K.F., Picolo, G., Chudzinski-Tavassi, A.M. & Cury, Y. Harnessing the knowledge of animal toxins to generate drugs. Pharmacol. Res. http://dx.doi.org/10.1016/j.phrs.2016.01.009 (2016).

  3. Safavi-Hemami, H. et al. Specialized insulin is used for chemical warfare by fish-hunting cone snails. Proc. Natl. Acad. Sci. USA 112, 1743–1748 (2015).

    Article  CAS  Google Scholar 

  4. Adams, M.J. et al. Structure of rhombohedral 2 zinc insulin crystals. Nature 224, 491–495 (1969).

    Article  CAS  Google Scholar 

  5. Owens, D.R. New horizons: alternative routes for insulin therapy. Nat. Rev. Drug Discov. 1, 529–540 (2002).

    Article  CAS  Google Scholar 

  6. Bao, S.J., Xie, D.L., Zhang, J.P., Chang, W.R. & Liang, D.C. Crystal structure of desheptapeptide(B24–B30)insulin at 1.6 A resolution: implications for receptor binding. Proc. Natl. Acad. Sci. USA 94, 2975–2980 (1997).

    Article  CAS  Google Scholar 

  7. Walewska, A. et al. Integrated oxidative folding of cysteine/selenocysteine containing peptides: improving chemical synthesis of conotoxins. Angew. Chem. Int. Edn. Engl. 48, 2221–2224 (2009).

    Article  CAS  Google Scholar 

  8. Denley, A. et al. Structural determinants for high-affinity binding of insulin-like growth factor II to insulin receptor (IR)-A, the exon 11 minus isoform of the IR. Mol. Endocrinol. 18, 2502–2512 (2004).

    Article  CAS  Google Scholar 

  9. Timofeev, V.I. et al. X-ray investigation of gene-engineered human insulin crystallized from a solution containing polysialic acid. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 66, 259–263 (2010).

    Article  CAS  Google Scholar 

  10. Weiss, M.A. The structure and function of insulin: decoding the TR transition. Vitam. Horm. 80, 33–49 (2009).

    Article  CAS  Google Scholar 

  11. Menting, J.G. et al. How insulin engages its primary binding site on the insulin receptor. Nature 493, 241–245 (2013).

    Article  CAS  Google Scholar 

  12. Menting, J.G. et al. Protective hinge in insulin opens to enable its receptor engagement. Proc. Natl. Acad. Sci. USA 111, E3395–E3404 (2014).

    Article  CAS  Google Scholar 

  13. Muttenthaler, M., Ramos, Y.G., Feytens, D., de Araujo, A.D. & Alewood, P.F. p-Nitrobenzyl protection for cysteine and selenocysteine: a more stable alternative to the acetamidomethyl group. Biopolymers 94, 423–432 (2010).

    Article  CAS  Google Scholar 

  14. Smith, G.D., Pangborn, W.A. & Blessing, R.H. The structure of T6 human insulin at 1.0 A resolution. Acta Crystallogr. D Biol. Crystallogr. 59, 474–482 (2003).

    Article  Google Scholar 

  15. Rivier, J. et al. Total synthesis and further characterization of the γ-carboxyglutamate-containing “sleeper” peptide from Conus geographus venom. Biochemistry 26, 8508–8512 (1987).

    Article  CAS  Google Scholar 

  16. Galande, A.K., Weissleder, R. & Tung, C.-H. An effective method of on-resin disulfide bond formation in peptides. J. Comb. Chem. 7, 174–177 (2005).

    Article  CAS  Google Scholar 

  17. Houtman, J.C. et al. Studying multisite binary and ternary protein interactions by global analysis of isothermal titration calorimetry data in SEDPHAT: application to adaptor protein complexes in cell signaling. Protein Sci. 16, 30–42 (2007).

    Article  CAS  Google Scholar 

  18. Laue, T., Shah, D., Ridgeway, T. & Pelletier, S. in Analytical Ultracentrifugation in Biochemistry and Polymer Science (eds. Harding, S., Rowe, A.J. & Horton, J.C.) 90–125 (Royal Society of Chemistry, 1992).

  19. Dai, Q., Dong, M., Liu, Z., Prorok, M. & Castellino, F.J. Ca 2+-induced self-assembly in designed peptides with optimally spaced γ-carboxyglutamic acid residues. J. Inorg. Biochem. 105, 52–57 (2011).

    Article  CAS  Google Scholar 

  20. Cnudde, S.E., Prorok, M., Jia, X., Castellino, F.J. & Geiger, J.H. The crystal structure of the calcium-bound con-G[Q6A] peptide reveals a novel metal-dependent helical trimer. J. Biol. Inorg. Chem. 16, 257–266 (2011).

    Article  CAS  Google Scholar 

  21. Chen, Z. et al. Conformational changes in conantokin-G induced upon binding of calcium and magnesium as revealed by NMR structural analysis. J. Biol. Chem. 273, 16248–16258 (1998).

    Article  CAS  Google Scholar 

  22. Kabsch, W. Integration, scaling, space-group assignment and post-refinement. Acta Crystallogr. D Biol. Crystallogr. 66, 133–144 (2010).

    Article  CAS  Google Scholar 

  23. McCoy, A.J. et al. Phaser crystallographic software. J. Appl. Crystallogr. 40, 658–674 (2007).

    Article  CAS  Google Scholar 

  24. 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  Google Scholar 

  25. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D Biol. Crystallogr. 60, 2126–2132 (2004).

    Article  Google Scholar 

  26. Webb, B. & Sali, A. Comparative protein structure modeling using MODELLER. Curr. Protoc. Bioinformatics 47, 5.6 (2014).

    Article  Google Scholar 

  27. Hua, Q.X. et al. Structure of a protein in a kinetic trap. Nat. Struct. Biol. 2, 129–138 (1995).

    Article  CAS  Google Scholar 

  28. Sparrow, L.G. et al. N-linked glycans of the human insulin receptor and their distribution over the crystal structure. Proteins 71, 426–439 (2008).

    Article  CAS  Google Scholar 

  29. Pronk, S. et al. GROMACS 4.5: a high-throughput and highly parallel open source molecular simulation toolkit. Bioinformatics 29, 845–854 (2013).

    Article  CAS  Google Scholar 

  30. Guvench, O. et al. CHARMM additive all-atom force field for carbohydrate derivatives and its utility in polysaccharide and carbohydrate-protein modeling. J. Chem. Theory Comput. 7, 3162–3180 (2011).

    Article  CAS  Google Scholar 

  31. Best, R.B. et al. Optimization of the additive CHARMM all-atom protein force field targeting improved sampling of the backbone ϕ, ψ and side-chain χ(1) and χ(2) dihedral angles. J. Chem. Theory Comput. 8, 3257–3273 (2012).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

R.S.N. acknowledges fellowship support from the National Health and Medical Research Council of Australia (NHMRC). N.A.S. acknowledges receipt of an Australian Postgraduate Award scholarship. This work was supported in part by National Institutes of Health grants GM 48677 (to B.M.O. and J.E.R., a subcontractor at Sentia Medical Sciences), by NHMRC Project Grant APP1058233 (to M.C.L.) and by the Utah Science and Technology Initiative (USTAR, to D.H.-C.C.). H.S.-H. acknowledges fellowship support from the European Commission (CONBIOS 330486). Aspects of this work were made possible through Victorian State Government Operational Infrastructure Support, the Australian Government NHMRC IRIISS and a pilot grant from the University of Utah Diabetes and Metabolism Center. We thank A. Morrione (Thomas Jefferson University) for providing cells. Part of this research was undertaken on the MX2 beamline at the Australian Synchrotron (Victoria, Australia).

Author information

Authors and Affiliations

Authors

Contributions

J.G.M. and M.C.L. performed crystallography; M.C.L., R.S.N., H.S.-H. and B.J.S. directed research; B.M.O., H.S.-H., R.S.N. and M.C.L. designed the study; B.E.F. and D.H.-C.C. performed experiments and analyzed data; J.G., C.M. and J.E. synthesized peptides and analyzed data; M.M.D. performed experiments; C.A.M. performed ultracentrifugation experiments, N.A.S. and B.J.S. performed computer modeling, J.E.R. supervised peptide synthesis, and M.C.L., R.S.N., H.S.-H. and B.J.S. wrote the manuscript.

Corresponding author

Correspondence to Michael C Lawrence.

Ethics declarations

Competing interests

M.C.L.'s and D.H.C.'s research activities are partially funded by Sanofi (Germany).

Integrated supplementary information

Supplementary Figure 1 Arrangement of Con-Ins G1 monomers around the crystallographic four-fold axis (stereo).

The four Con-Ins G1 monomers coordinate an apparent single off-axis sulfate molecules (centre), modelled with unrestrained coordinates into a relatively featureless blob (not shown) of difference electron density lying on the crystallographic four-fold axis. The ion forms part of a charge-compensated cluster comprising the amino-terminal group of GlyA1 and a side-chain carboxylate of GlaA4 from each Con-Ins G1 monomer. The Con-Ins G1 A chains are in pink and the B chains in light blue.

Supplementary Figure 2 Amino acid sequence and RP-HPLC profile of fully oxidized Con-Ins G1.

The left-hand panel shows the amino acid sequence of fully-oxidized Con-Ins G1 (top: A chain; bottom, B chain). O: hydroxyproline, γ: γ-carboxyglutamate, *: amidated C-terminus. The right-hand panel shows the RP-HPLC profile. RP-HPLC conditions are: C18 Vydac RP-HPLC column, linear gradient ranging from 15 to 45% of solvent B in 30 min with 1 mL / min flow rate monitored at 220 nm.

Supplementary Figure 3 Amino acid sequence and RP-HPLC profile of fully oxidized PTM-free sCon-Ins G1.

The left-hand panel shows the amino acid sequence of fully-oxidized PTM-free sCon-Ins G1 (top: A chain; bottom, B chain). Residues in bold indicate site of mutation; U: selenocysteine, *: amidated C-terminus. The right-hand panel shows the RP-HPLC profile. RP-HPLC conditions are: C18 Vydac RP-HPLC column, linear gradient ranging from 15 to 45% of solvent B in 30 min with 1 mL / min flow rate monitored at 220 nm.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–3 and Supplementary Note (PDF 515 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Menting, J., Gajewiak, J., MacRaild, C. et al. A minimized human insulin-receptor-binding motif revealed in a Conus geographus venom insulin. Nat Struct Mol Biol 23, 916–920 (2016). https://doi.org/10.1038/nsmb.3292

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nsmb.3292

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing