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Counting polymers moving through a single ion channel

Abstract

THE change in conductance of a small electrolyte-filled capillary owing to the passage of sub-micrometre-sized particles has long been used for particle counting and sizing. A commercial device for such measurements, the Coulter counter, is able to detect particles of sizes down to several tenths of a micrometre1–3. Nuclepore technology (in which pores are etched particle tracks) has extended the lower limit of size detection to 60-nm particles by using a capillary of diameter 0.45 μm (ref. 4). Here we show that natural channel-forming peptides incorporated into a bilayer lipid membrane can be used to detect the passage of single molecules with gyration radii as small as 5–15 Å. From our experiments with alamethicin pores we infer both the average number and the diffusion coefficients of poly(ethylene glycol) molecules in the pore. Our approach provides a means of observing the statistics and mechanics of flexible polymers moving within the confines of precisely defined single-molecule structures.

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References

  1. Kubitschek, H. E. Nature 182, 234–235 (1958).

    Article  ADS  CAS  Google Scholar 

  2. Allen, T. in Particle Size Analysis 110–127 (Society for Analytical Chemistry Publishers, London, 1967).

    Google Scholar 

  3. Bunville, L. G. in Modern Methods of Particle Size Analysis (ed. Barth, H. G.) 1–42 (Wiley, New York, 1984).

    Google Scholar 

  4. DeBlois, R. W., Bean, C. P. & Wesley, R. K. A. J. Colloid Interface Sci. 61, 323–335 (1977).

    Article  ADS  CAS  Google Scholar 

  5. Bezrukov, S. M. & Vodyanoy, I. Biophys. J. 64, 16–25 (1993).

    Article  ADS  CAS  Google Scholar 

  6. Sansom, M. S. P. Eur. Biophys. J. 22, 105–124 (1993).

    Article  CAS  Google Scholar 

  7. Hall, J. E., Vodyanoy, I., Balasubramanian, T. M. & Marshall, G. R. Biophys. J. 45, 233–247 (1984).

    Article  ADS  CAS  Google Scholar 

  8. Vodyanoy, I., Bezrukov, S. M. & Parsegian, V. A. Biophys. J. 65, 2097–2105 (1993).

    Article  ADS  CAS  Google Scholar 

  9. Krasilnikov, O. V., Sabirov, R. Z., Ternovsky, V. I., Merzliak, P. G. & Muratkhodjaev, J. N. FEMS Microbiol. Imunol. 105, 93–100 (1992).

    Article  Google Scholar 

  10. Bezrukov, S. M. & Vodyanoy, I. in Membrane Electrochemistry (Advances in Chemistry Ser. No. 235, American Chemical Soc, Washington DC, in the press).

  11. Feher, G. & Weissman, M. Proc. natn. Acad. Sci. U.S.A. 70, 870–875 (1973).

    Article  ADS  CAS  Google Scholar 

  12. Kuga, S. J. Chromatogr. 206, 449–461 (1981).

    Article  CAS  Google Scholar 

  13. Bean, C. P. in Membranes (ed. Eisenman, G.) 1–54 (Dekker, New York, 1972).

    Google Scholar 

  14. Couper, A. & Stepto, R. F. T. Trans. Faraday Soc. 65, 2486–2496 (1969).

    Article  CAS  Google Scholar 

  15. Hess, P. & Tsien, R. W. Nature 309, 453–456 (1984).

    Article  ADS  CAS  Google Scholar 

  16. Heinemann, S. H. & Sigworth, F. J. Biochim. biophys. Acta 987, 8–14 (1989).

    Article  CAS  Google Scholar 

  17. Simon, S. M. & Blobel, G. Cell 65, 371–380 (1991).

    Article  CAS  Google Scholar 

  18. Montal, M. & Mueller, P. Proc. natn. Acad. Sci. U.S.A. 69, 3561–3566 (1972).

    Article  ADS  CAS  Google Scholar 

  19. Balasubramanian, T. M. et al. J. Am. chem. Soc. 103, 6127–6132 (1981).

    Article  CAS  Google Scholar 

  20. Gordon, L. G. M. & Haydon, D. A. Phil. Trans. R. Soc. B 270, 433–447 (1975).

    Article  CAS  Google Scholar 

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Bezrukov, S., Vodyanoy, I. & Parsegian, V. Counting polymers moving through a single ion channel. Nature 370, 279–281 (1994). https://doi.org/10.1038/370279a0

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