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:

Unidirectional single-file transport of full-length proteins through a nanopore

An Author Correction to this article was published on 21 September 2023

This article has been updated

Abstract

The electrical current blockade of a peptide or protein threading through a nanopore can be used as a fingerprint of the molecule in biosensor applications. However, threading of full-length proteins has only been achieved using enzymatic unfolding and translocation. Here we describe an enzyme-free approach for unidirectional, slow transport of full-length proteins through nanopores. We show that the combination of a chemically resistant biological nanopore, α-hemolysin (narrowest part is ~1.4 nm in diameter), and a high concentration guanidinium chloride buffer enables unidirectional, single-file protein transport propelled by an electroosmotic effect. We show that the mean protein translocation velocity depends linearly on the applied voltage and translocation times depend linearly on length, resembling the translocation dynamics of ssDNA. Using a supervised machine-learning classifier, we demonstrate that single-translocation events contain sufficient information to distinguish their threading orientation and identity with accuracies larger than 90%. Capture rates of protein are increased substantially when either a genetically encoded charged peptide tail or a DNA tag is added to a protein.

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

Fig. 1: Enzyme-free full-length protein translocation through nanopores.
Fig. 2: Transport properties of unfolded protein analytes.
Fig. 3: MD simulation of ion, water and peptide transport through α-hemolysin.
Fig. 4: Unidirectional translocation and discrimination of MBP variants.
Fig. 5: Single-molecule fingerprinting of full-length MBP-D10 and GFP-D10.

Similar content being viewed by others

Data availability

All data used in this manuscript are available for download at https://figshare.com/s/5cd39ee415c62a316a6f.

Code availability

All data parsing (excluding DTW and GBC) were performed using the Pyth-ion package (https://github.com/wanunulab/Pyth-Ion) and figures were generated using Igor. For analysis, the raw 100 kHz nanopore current data was further low-pass filtered to 10 kHz using the low-pass filter function in Pyth-ion. DTW and GBC analyses were conducted via python scripts written and documented in Jupyter Notebooks, tslearn (v0.5.2)77, SciKit-Learn (v1.0.2)78, and a modified version of the PyPore79 nanopore data analysis library. The Jupyter notebook and associated files are available on GitHub (https://github.com/wanunulab/protein-gd). A detailed description of the DTW and GBC analyses is provided in Supplementary Figs. 26–33, Supplementary Tables 4–7 and Supplementary Notes 3 and 4.

Change history

References

  1. Shendure, J. et al. DNA sequencing at 40: past, present and future. Nature 550, 345–353 (2017).

    Article  CAS  PubMed  Google Scholar 

  2. Ameur, A., Kloosterman, W. P. & Hestand, M. S. Single-molecule sequencing: towards clinical applications. Trends Biotechnol. 37, 72–85 (2019).

    Article  CAS  PubMed  Google Scholar 

  3. Eid, J. et al. Real-time DNA sequencing from single polymerase molecules. Science 323, 133 (2009).

    Article  CAS  PubMed  Google Scholar 

  4. Venkatesan, B. M. & Bashir, R. Nanopore sensors for nucleic acid analysis. Nat. Nanotechnol. 6, 615–624 (2011).

    Article  CAS  PubMed  Google Scholar 

  5. Deamer, D., Akeson, M. & Branton, D. Three decades of nanopore sequencing. Nat. Biotechnol. 34, 518–524 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Smith, L. M. et al. Proteoform: a single term describing protein complexity. Nat. Methods 10, 186–187 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Bogaert, A., Fernandez, E. & Gevaert, K. N-terminal proteoforms in human disease. Trends Biochem. Sci. 45, 308–320 (2020).

    Article  CAS  PubMed  Google Scholar 

  8. Tolsma, T. O. & Hansen, J. C. Post-translational modifications and chromatin dynamics. Essays Biochem. 63, 89–96 (2019).

    Article  CAS  PubMed  Google Scholar 

  9. Conibear, A. C. Deciphering protein post-translational modifications using chemical biology tools. Nat. Rev. Chem. 4, 674–695 (2020).

    Article  CAS  PubMed  Google Scholar 

  10. MacCoss, M. J., Alfaro, J., Wanunu, M., Faivre, D. A. & Slavov, N. Sampling the proteome by emerging single-molecule and mass-spectrometry methods. Preprint at arXiv https://doi.org/10.48550/arXiv.2208.00530 (2022).

  11. Slavov, N. Single-cell protein analysis by mass spectrometry. Curr. Opin. Chem. Biol. 60, 1–9 (2021).

    Article  CAS  PubMed  Google Scholar 

  12. Specht, H. & Slavov, N. Transformative opportunities for single-cell proteomics. J. Proteome Res. 17, 2565–2571 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Specht, H. et al. Single-cell proteomic and transcriptomic analysis of macrophage heterogeneity using SCoPE2. Genome Biol. 22, 50 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  14. Alfaro, J. A. et al. The emerging landscape of single-molecule protein sequencing technologies. Nat. Methods 18, 604–617 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Zhao, Y. et al. Single-molecule spectroscopy of amino acids and peptides by recognition tunnelling. Nat. Nanotechnol. 9, 466–473 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Kennedy, E., Dong, Z., Tennant, C. & Timp, G. Reading the primary structure of a protein with 0.07 nm3 resolution using a subnanometre-diameter pore. Nat. Nanotechnol. 11, 968–976 (2016).

    Article  CAS  PubMed  Google Scholar 

  17. Swaminathan, J. et al. Highly parallel single-molecule identification of proteins in zeptomole-scale mixtures. Nat. Biotechnol. 36, 1076–1082 (2018).

    Article  CAS  Google Scholar 

  18. van Ginkel, J. et al. Single-molecule peptide fingerprinting. Proc. Natl Acad. Sci. 115, 3338–3343 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  19. Restrepo-Pérez, L., Joo, C. & Dekker, C. Paving the way to single-molecule protein sequencing. Nat. Nanotechnol. 13, 786–796 (2018).

    Article  PubMed  Google Scholar 

  20. Stefureac, R., Long, Y.-t, Kraatz, H.-B., Howard, P. & Lee, J. S. Transport of α-helical peptides through α-hemolysin and aerolysin pores. Biochemistry 45, 9172–9179 (2006).

    Article  CAS  PubMed  Google Scholar 

  21. Movileanu, L. Squeezing a single polypeptide through a nanopore. Soft Matter 4, 925–931 (2008).

    Article  CAS  PubMed  Google Scholar 

  22. Rodriguez-Larrea, D. & Bayley, H. Multistep protein unfolding during nanopore translocation. Nat. Nanotechnol. 8, 288–295 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Rosen, C. B., Bayley, H. & Rodriguez-Larrea, D. Free-energy landscapes of membrane co-translocational protein unfolding. Commun. Biol. 3, 160 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Payet, L. et al. Thermal unfolding of proteins probed at the single molecule level using nanopores. Anal. Chem. 84, 4071–4076 (2012).

    Article  CAS  PubMed  Google Scholar 

  25. Soni, N., Freundlich, N., Ohayon, S., Huttner, D. & Meller, A. Single-file translocation dynamics of SDS-denatured, whole proteins through sub-5 nm solid-state nanopores. ACS Nano 16, 11405–11414 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Oukhaled, G. et al. Unfolding of proteins and long transient conformations detected by single nanopore recording. Phys. Rev. Lett. 98, 158101 (2007).

    Article  CAS  PubMed  Google Scholar 

  27. Pastoriza-Gallego, M. et al. Dynamics of unfolded protein transport through an aerolysin pore. J. Am. Chem. Soc. 133, 2923–2931 (2011).

    Article  CAS  PubMed  Google Scholar 

  28. Merstorf, C. et al. Wild type, mutant protein unfolding and phase transition detected by single-nanopore recording. ACS Chem. Biol. 7, 652–658 (2012).

    Article  CAS  PubMed  Google Scholar 

  29. Pastoriza-Gallego, M. et al. Evidence of unfolded protein translocation through a protein nanopore. ACS Nano 8, 11350–11360 (2014).

    Article  CAS  PubMed  Google Scholar 

  30. Cressiot, B. et al. Protein transport through a narrow solid-state nanopore at high voltage: experiments and theory. ACS Nano 6, 6236–6243 (2012).

    Article  CAS  PubMed  Google Scholar 

  31. Keyser, U. F. et al. Direct force measurements on DNA in a solid-state nanopore. Nat. Phys. 2, 473–477 (2006).

    Article  CAS  Google Scholar 

  32. Nivala, J., Marks, D. B. & Akeson, M. Unfoldase-mediated protein translocation through an alpha-hemolysin nanopore. Nat. Biotechnol. 31, 247–250 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. Nivala, J., Mulroney, L., Li, G., Schreiber, J. & Akeson, M. Discrimination among protein variants using an unfoldase-coupled nanopore. ACS Nano 8, 12365–12375 (2014).

    Article  CAS  PubMed  Google Scholar 

  34. Yan, S. et al. Single molecule ratcheting motion of peptides in a Mycobacterium smegmatis porin A (MspA) nanopore. Nano Lett. 21, 6703–6710 (2021).

    Article  CAS  PubMed  Google Scholar 

  35. Chen, Z. et al. Controlled movement of ssDNA conjugated peptide through Mycobacterium smegmatis porin A (MspA) nanopore by a helicase motor for peptide sequencing application. Chem. Sci. 12, 15750–15756 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Brinkerhoff, H., Kang Albert, S. W., Liu, J., Aksimentiev, A. & Dekker, C. Multiple rereads of single proteins at single-amino acid resolution using nanopores. Science 374, 1509–1513 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. Kang, X., Alibakhshi, M. A. & Wanunu, M. One-pot species release and nanopore detection in a voltage-stable lipid bilayer platform. Nano Lett. 19, 9145–9153 (2019).

    Article  CAS  PubMed  Google Scholar 

  38. Yu, L. et al. Stable polymer bilayers for protein channel recordings at high guanidinium chloride concentrations. Biophys. J. 120, 1537–1541 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. Haynes, W. M. CRC Handbook of Chemistry and Physics (CRC Press, 2016).

  40. Perkins, S. J. Protein volumes and hydration effects. Eur. J. Biochem. 157, 169–180 (1986).

    Article  CAS  PubMed  Google Scholar 

  41. Liu, G. P., Topping, T. B., Cover, W. H. & Randall, L. L. Retardation of folding as a possible means of suppression of a mutation in the leader sequence of an exported protein. J. Biol. Chem. 263, 14790–14793 (1988).

    Article  CAS  PubMed  Google Scholar 

  42. Sheshadri, S., Lingaraju, G. M. & Varadarajan, R. Denaturant mediated unfolding of both native and molten globule states of maltose binding protein are accompanied by large deltaCp’s. Protein Sci. 8, 1689–1695 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Nakane, J., Akeson, M. & Marziali, A. Evaluation of nanopores as candidates for electronic analyte detection. Electrophoresis 23, 2592–2601 (2002).

    Article  CAS  PubMed  Google Scholar 

  44. Meller, A., Nivon, L. & Branton, D. Voltage-driven DNA translocations through a nanopore. Phys. Rev. Lett. 86, 3435–3438 (2001).

    Article  CAS  PubMed  Google Scholar 

  45. Meller, A. & Branton, D. Single molecule measurements of DNA transport through a nanopore. Electrophoresis 23, 2583–2591 (2002).

    Article  CAS  PubMed  Google Scholar 

  46. Hornblower, B. et al. Single-molecule analysis of DNA-protein complexes using nanopores. Nat. Methods 4, 315–317 (2007).

    Article  CAS  PubMed  Google Scholar 

  47. Henrickson, S. E., Misakian, M., Robertson, B. & Kasianowicz, J. J. Driven DNA transport into an asymmetric nanometer-scale pore. Phys. Rev. Lett. 85, 3057–3060 (2000).

    Article  CAS  PubMed  Google Scholar 

  48. Mathé, J., Aksimentiev, A., Nelson, D. R., Schulten, K. & Meller, A. Orientation discrimination of single-stranded DNA inside the α-hemolysin membrane channel. Proc. Natl Acad. Sci. USA 102, 12377–12382 (2005).

    Article  PubMed  PubMed Central  Google Scholar 

  49. Yang, G. et al. Solid-state synthesis and mechanical unfolding of polymers of T4 lysozyme. Proc. Natl Acad. Sci. USA 97, 139 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Aksimentiev, A. & Schulten, K. Imaging α-hemolysin with molecular dynamics: ionic conductance, osmotic permeability, and the electrostatic potential map. Biophys. J. 88, 3745–3761 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Doina, P. & Whye, T. Y. (eds.). Soft-DTW: a differentiable loss function for time-series. Proceedings of the 34th International Conference on Machine Learning Vol. 70, pp. 894–903 (PMLR, 2017).

  52. Larkin, J. et al. High-bandwidth protein analysis using solid-state nanopores. Biophys. J. 106, 696–704 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  53. Ling, D. Y. & Ling, X. S. On the distribution of DNA translocation times in solid-state nanopores: an analysis using Schrödinger’s first-passage-time theory. J. Phys. Condens. Matter 25, 375102 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  54. Li, J. & Talaga, D. S. The distribution of DNA translocation times in solid-state nanopores. J. Phys. Condens. Matter 22, 454129 (2010).

    Article  PubMed  PubMed Central  Google Scholar 

  55. Talaga, D. S. & Li, J. Single-molecule protein unfolding in solid state nanopores. J. Am. Chem. Soc. 131, 9287–9297 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. Pavlenok, M., Yu, L., Herrmann, D., Wanunu, M. & Niederweis, M. Control of subunit stoichiometry in single-chain MspA nanopores. Biophys. J. https://doi.org/10.1016/j.bpj.2022.01.022 (2022).

    Article  PubMed  PubMed Central  Google Scholar 

  57. Ouldali, H. et al. Electrical recognition of the twenty proteinogenic amino acids using an aerolysin nanopore. Nat. Biotechnol. 38, 176–181 (2020).

    Article  CAS  PubMed  Google Scholar 

  58. Versloot, R. C. A., Straathof, S. A. P., Stouwie, G., Tadema, M. J. & Maglia, G. β-Barrel nanopores with an acidic–aromatic sensing region identify proteinogenic peptides at low pH. ACS Nano https://doi.org/10.1021/acsnano.1c11455 (2022).

    Article  PubMed  PubMed Central  Google Scholar 

  59. Versloot, R. C. A. et al. Quantification of protein glycosylation using nanopores. Nano Lett. 22, 5357–5364 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  60. Huang, G. et al. PlyAB nanopores detect single amino acid differences in folded haemoglobin from blood. Angew. Chem. Int. Ed. 61, e202206227 (2022).

    Article  CAS  Google Scholar 

  61. Noakes, M. T. et al. Increasing the accuracy of nanopore DNA sequencing using a time-varying cross membrane voltage. Nat. Biotechnol. 37, 651–656 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  62. Muthukumar, M. Polymer translocation through a hole. J. Chem. Phys. 111, 10371–10374 (1999).

    Article  CAS  Google Scholar 

  63. Ammenti, A., Cecconi, F., Marini Bettolo Marconi, U. & Vulpiani, A. A statistical model for translocation of structured polypeptide chains through nanopores. J. Phys. Chem. B 113, 10348–10356 (2009).

    Article  CAS  PubMed  Google Scholar 

  64. Phillips, J. C. et al. Scalable molecular dynamics on CPU and GPU architectures with NAMD. J. Chem. Phys. 153, 044130 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  65. Klauda, J. B. et al. Update of the CHARMM all-atom additive force field for lipids: validation on six lipid types. J. Phys. Chem. B 114, 7830–7843 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  66. Yoo, J. & Aksimentiev, A. New tricks for old dogs: improving the accuracy of biomolecular force fields by pair-specific corrections to non-bonded interactions. Phys. Chem. Chem. Phys. 20, 8432–8449 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. Miyamoto, S. & Kollman, P. A. Settle: an analytical version of the SHAKE and RATTLE algorithm for rigid water models. J. Comput. Chem. 13, 952–962 (1992).

    Article  CAS  Google Scholar 

  68. Andersen, H. C. Rattle: a ‘velocity’ version of the shake algorithm for molecular dynamics calculations. J. Comput. Phys. 52, 24–34 (1983).

    Article  CAS  Google Scholar 

  69. Darden, T., York, D. & Pedersen, L. Particle mesh Ewald: an Nlog(N) method for Ewald sums in large systems. J. Chem. Phys. 98, 10089–10092 (1993).

    Article  CAS  Google Scholar 

  70. Jo, S., Kim, T., Iyer, V. G. & Im, W. CHARMM-GUI: a web-based graphical user interface for CHARMM. J. Comput. Chem. 29, 1859–1865 (2008).

    Article  CAS  PubMed  Google Scholar 

  71. Song, L. et al. Structure of staphylococcal α-hemolysin, a heptameric transmembrane pore. Science 274, 1859–1865 (1996).

    Article  CAS  PubMed  Google Scholar 

  72. Jorgensen, W. L., Chandrasekhar, J., Madura, J. D., Impey, R. W. & Klein, M. L. Comparison of simple potential functions for simulating liquid water. J. Chem. Phys. 79, 926–935 (1983).

    Article  CAS  Google Scholar 

  73. Martyna, G. J., Tobias, D. J. & Klein, M. L. Constant pressure molecular dynamics algorithms. J. Chem. Phys. 101, 4177–4189 (1994).

    Article  CAS  Google Scholar 

  74. Duan, X. & Quiocho, F. A. Structural evidence for a dominant role of nonpolar interactions in the binding of a transport/chemosensory receptor to its highly polar ligands. Biochemistry 41, 706–712 (2002).

    Article  CAS  PubMed  Google Scholar 

  75. Humphrey, W., Dalke, A. & Schulten, K. VMD: visual molecular dynamics. J. Mol. Graph. 14, 33–38 (1996).

    Article  CAS  PubMed  Google Scholar 

  76. Li, H., Robertson, A. D. & Jensen, J. H. Very fast empirical prediction and rationalization of protein pKa values. Proteins Struct. Funct. Bioinf. 61, 704–721 (2005).

    Article  CAS  Google Scholar 

  77. Tavenard, R. et al. Tslearn, a machine learning toolkit for time series data. J. Mach. Learn. Res. 21, 1–6 (2020).

    Google Scholar 

  78. Pedregosa, F. et al. Scikit-learn: machine learning in Python. J. Mach. Learn. Res. 12, 2825–2830 (2011).

    Google Scholar 

  79. Schreiber, J. & Karplus, K. Analysis of nanopore data using hidden Markov models. Bioinformatics 31, 1897–1903 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

We thank C. McCormick for assistance with editing the manuscript for clarity, and N. Slavov for helpful discussions regarding protein sequencing. We acknowledge funding from the National Institutes of Health under grants HG011087 (to M.W.) and GM115442 (to M.C.), and the National Science Foundation under grant PHY-1430124 (to A.A.). The supercomputer time was provided through the XSEDE allocation grant (MCA05S028) and the Leadership Resource Allocation MCB20012 on Frontera of the Texas Advanced Computing Center.

Author information

Authors and Affiliations

Authors

Contributions

L.Y. and M.W. conceived the project and designed the experiments. L.Y. developed the experimental protocol, carried out the experiments and analyzed the protein translocation data. X.K. and L.Y. fabricated the SU-8 wedge-on-pillar chips used in the experiments. F.L. and M.C. prepared and purified the protein samples. B.M. and A.A. designed and conducted the MD simulations. A.M. and A.F. performed the data analysis described in ‘protein-specific current signals’ (SDTW and GBC) and wrote the respective sections of the manuscript. J.C.F. performed the DNA–protein conjugation experiments. L.Y., B.M., A.A. and M.W. wrote the first draft of the manuscript, and all authors commented and edited it.

Corresponding author

Correspondence to Meni Wanunu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Biotechnology thanks Jeff Nivala and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–33, Supplementary notes 1–4 and Supplementary Tables 1–7.

Reporting Summary

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yu, L., Kang, X., Li, F. et al. Unidirectional single-file transport of full-length proteins through a nanopore. Nat Biotechnol 41, 1130–1139 (2023). https://doi.org/10.1038/s41587-022-01598-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41587-022-01598-3

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