Single molecule force spectroscopy on polysaccharides by atomic force microscopy

Science

Volumn 275, Issue 5304, 1997, Pages 1295-1297

  Rief, Matthias ^a   Oesterhelt, Filipp ^a   Heymann, Berthold ^a   Gaub, Hermann E ^a  

^a UNIVERSITY OF MUNICH   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

POLYSACCHARIDE;

ARTICLE; ATOMIC FORCE MICROSCOPY; CONFORMATIONAL TRANSITION; ENTROPY; MOLECULAR DYNAMICS; PRIORITY JOURNAL;

EID: 0031042739     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.275.5304.1295     Document Type: Article

References (33)

1. S. B. Smith, Y. Cui, C. Bustamante, Science 271, 795 (1996).
2. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
3. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
4. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
5. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
6. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
7. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
8. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
9. P. Cluzel et al., ibid., p. 792; T. T. Perkins, D. E. Smith, R. G. Larson, S. Chu, ibid. 268, 83 (1995); M. Radmacher, M. Fritz, H. G. Hansma, P. K. Hansma, ibid. 265, 1577 (1994); J. Käs, H. Strey, E. Sackmann, Nature 368, 226 (1994); J. T. Finer, R. M. Simmons, J. A. Spudich, ibid., p. 113; K. Svoboda, C. F. Schmidt, B. J. Schnapp, S. M. Block, ibid. 365, 721 (1993); U. Dammer et al., Biophys. J. 70, 2437 (1996); P. Hinterdorfer, W. Baumgartner, H. J. Gruber, K. Schilcher, H. Schindler, Proc. Natl. Acad. Sci. U.S.A. 93, 3477 (1996).
10. E.-L. Florin, V. T. Moy, H. E. Gaub, Science 264, 415 (1994).
11. V. T. Moy, E. L. Florin, H. E. Gaub, ibid. 266, 257 (1994).
12. G. U. Lee, D. A. Kidwell, R. J. Colton, Langmuir 10, 354 (1994).
13. G. U. Lee, L. A. Chrisey, R. J. Colton, Science 266, 771 (1994).
14. E. Stenberg, B. Persson, H. Roos, C. Urbaniczky, J. Colloid Interface Sci. 143, 513 (1991).
15. Under conditions where the deformation of this molecular pair is less than that of the molecular couplers, the elongation of the entire system is dominated by the deformation of the couplers. The specific bond between molecular binding pairs may thus be used as a reversible coupling mechanism of a long and flexible molecule whose deformation is to be investigated.
16. This mode is particularly advantageous when the density of functional groups is high or when the polymeric material has a low density, such as in the outer layers of agarose beads used in earlier studies. On the dextran films used here the radius of the AFM tip is on the order of the mean distance of two grafted dextran coils. In this case an interaction of only a few polymer strands with the tip is likely. A noncommercial AFM, customized for force measurements, was used to do the experiments. Piezo nonlinearities were corrected with a strain gauge. The spring constants of the cantilevers (Digital Instruments, Santa Barbara, CA) were calibrated by measuring their thermal excitation (23). Measured values ranged from 25 to 120 mN/m. All experiments were carried out in phosphate-buffered saline (150 mM NaCl, pH 7.4).
17. Because the streptavidin molecules are distributed statistically along the polysaccharide chain, it is very likely that the tip does not pick up the end of the chain. Because the dextran is only branched and not cross-linked, the free end is dangling, and as a result, the apparent length of the polymer is reduced.
18. segment are related to monomers and not to the Kuhn segments. In order to fit the data by this model, it was assumed that the point of zero extension is where the tip meets the hard substrate.
19. M. Rief, F. Oesterhelt, B. Heymann, H. E. Gaub, data not shown.
20. It is very likely though, that by pulling at one end of the coiled polymer while keeping the other end fixed, we do tighten random knots. The measured scaling of the elastic properties of the polymer indicates that these knots are compact and do not contribute significantly to the elasticity of the polymer. Whether or not these knots disentangle upon expansion is not known yet. A marked contribution from the interchain interaction can also be excluded. In the extension regime, where a measurable tension is built up in the polymer, the largest part of the extended polymer is far out of reach of the other poymers of the brush.
21. Equilibration (300 K) and pulling simulations were done with the program EGO (24), which uses the CHARMM force field (25). For modeling and minimization of the structure containing five glucose units, the program QUANTA (Molecular Simulations, Waltham, MA) was used. All simulations were done in water.
22. segment of the Langevin function (11) was replaced by the calculated elasticity and normalized (18).
23. The cantilevers were silanized in dimethyl-dichlorosilane (Sigma, Deisenhofen, Germany) vapor and rinsed with acetone. Commercially available carboxymethylated dextran films on gold (Sensor Chip CM5, Pharmacia Biosensor AB, Uppsala, Sweden) were used as samples in order to be able to compare the results to the similarly treated but streptavidin-functionalized dextrans used before.
24. A fit of the low force regime results in the same Kuhn length and segment elasticity as found in Fig. 1.
25. The polymer extension was divided by the contour length and multiplied with the length of the monomer. This normalization allows the comparison between the force profiles of dextran filaments of different lengths.
26. Obviously contributions to the elastic properties due to interchain interactions do not play a measurable role in our experiment. Interchain interactions as well as nonlocal intrachain interactions like complex knots would scale nonlinearly and would not result in the observed strict linear scaling with length.
27. When measured with the same cantilever the variation of these values is <5% so that the transition is now routinely used for internal force calibration.
28. H. Grubmüller, B. Heymann, P. Tavan, Science 271, 997 (1995).
29. A decrease of the transition force with the pulling velocity could also be observed in our dextran simulations.
30. E. L. Florin et al., Biosens. Bioelectronics 10, 895 (1995).
31. M. Eichinger, H. Grubmüller, H. Heller, User Manual for EGO_VIII, Release 2.0 (Theoretische Biophysik, Institut fuer Medizinische Optik, Universität Muenchen, 1995).
32. B. R. Brooks et al., J. Comp. Chem. 4, 187 (1983).
33. Supported by the Deutsche Forschungsgemeinschaft and a Max-Planck research award. We gratefully acknowledge helpful discussions with P. Tavan, H. Grubmüller, M. Ludwig, and S. Lofas and inspiring advice from J. I. Brauman.