Preferential solvation within hydrophilic nanocavities and its effect on the folding of cholate foldamers

Journal of the American Chemical Society

Volumn 129, Issue 1, 2007, Pages 218-225

  Zhao, Yan ^a   Zhong, Zhenqi ^a   Ryu, Eui Hyun ^a  

^a IOWA STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CONCENTRATION (PROCESS); FLUORESCENCE; HYDROPHILICITY; MOLECULAR DYNAMICS; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; OLIGOMERS;

CHOLATE FOLDAMERS; MICROPHASE SEPARATION; MOLECULAR BASKET; POLAR SOLVENT;

NANOTECHNOLOGY;

ACETIC ACID ETHYL ESTER; ALCOHOL; CHOLIC ACID DERIVATIVE; DIMETHYL SULFOXIDE; HEXANE; OLIGOMER; SOLVENT;

ARTICLE; CHEMICAL ANALYSIS; CHEMICAL STRUCTURE; FLUORESCENCE SPECTROSCOPY; HYDROPHILICITY; NANOCHEMISTRY; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; SOLVATION; STRUCTURE ANALYSIS;

CHOLATES; MAGNETIC RESONANCE SPECTROSCOPY; MODELS, MOLECULAR; MOLECULAR CONFORMATION; NANOSTRUCTURES; SOLVENTS; SPECTROMETRY, FLUORESCENCE; WATER;

EID: 33846180694     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0671159     Document Type: Article

References (41)

1. For several recent reviews, see: (a) Gellman, S. H. Acc. Chem. Res. 1998, 31, 173-180.
2. (b) Kirshenbaum, K.; Zuckermann, R. N.; Dill, K. A. Curr. Opin. Struct. Biol. 1999, 9, 530-535.
3. (c) Stigers, K. D.; Soth, M. J.; Nowick, J. S. Curr. Opin. Chem. Biol. 1999, 3, 714-723.
4. (d) Hill, D. J.; Mio, M. J.; Prince, R. B.; Hughes, T. S.; Moore, J. S. Chem. Rev. 2001, 101, 3893-4012.
5. (e) Cubberley, M. S.; Iverson, B. L. Curr. Opin. Chem. Biol. 2001, 5, 650-653.
6. (f) Sanford, A. R.; Gong, B. Curr. Org. Chem. 2003, 7, 1649-1659.
7. (g) Martinek, T. A.; Fulop, F. Eur. J. Biochem. 2003, 270, 3657-3666.
8. (h) Cheng, R. P. Curr. Opin. Struct. Biol. 2004, 14, 512-520.
9. (i) Huc, I. Eur. J. Org. Chem. 2004, 17-29.
10. (j) Licini, G.; Pribs, L. J.; Scrimin, P. Eur. J. Org. Chem. 2005, 969-977.
11. Lokey, R. S.; Iverson, B. L. Nature 1995, 375, 303-305.
12. Stone, M. T.; Heemstra, J. M.; Moore, J. S. Acc. Chem. Res. 2006, 39, 11-20.
13. (a) Ryu, E.-H.; Zhao, Y. Org. Lett. 2004, 6, 3187-3189.
14. (b) Zhao, Y.; Ryu, E.-H. J. Org. Chem. 2005, 70, 7585-7591.
15. (c) Ryu, E.-H.; Jie, Y.; Zhong, Z.; Zhao, Y. J. Org. Chem. 2006, 71, 7205-7213.
16. (a) Zhao, Y.; Zhong, Z. J. Am. Chem. Soc. 2005, 127, 17894-17901.
17. (b) Zhao, Y.; Zhong, Z. J. Am. Chem. Soc. 2006, 128, 9988-9989.
18. (c) Zhao, Y.; Zhong, Z. Org. Lett. 2006, 8, 4715-4717.
19. The folded foldamer is a unimolecular mimic of a reversed micelle. A pool of polar solvent (e.g., water) often is also needed to stabilize reversed micelles formed by conventional surfactants, see: Fendler, J. H. Membrane Mimetic Chemistry; Wiley: New York, 1982; Chapter 3.
20. Solvophobic effects typically are used to describe direct association of poorly solvated molecular surfaces. Folding of the oligocholates is mediated by the entrapped polar solvents, thus making them different from most other solvophobic foldamers. Nevertheless, folding is still driven by the avoidance of the hydrophilic faces from the bulk solvent (a mostly nonpolar mixture). Thus, it is reasonable to refer to the folding as " solvophobically driven".
21. Marcus, Y. Solvent Mixtures: Properties and Selective Solvation; Marcel Dekker: New York, 2002.
22. Reichardt, C. Solvents and Solvent Effects in Organic Chemistry; Wiley: Weinheim, 2003: pp 38-42.
23. Strong solvent effects, which resulted from poor solvation of the interior of a host by large solvent molecules, have been reported in the literature. These effects are different from what is described in this paper. For examples, see: (a) Chapman, K. T.; Still, W. C. J. Am. Chem. Soc. 1989, 111, 3075-3077.
24. (b) Hof, F.; Craig, S. L.; Nuckolls, C.; Rebek, J., Jr. Angew. Chem., Int. Ed. 2002, 41, 1488-1508.
25. (c) Roncucci, P.; Pirondini, L.; Paderni, G.; Massera, C.; Dalcanale, E.; Azov, V. A.; Diederich, F. Chem.-Eur. J. 2006, 12, 4775-4784.
26. 2+ is therefore a direct indication for poor folding.
27. (a) Sandström, M.; Persson, I.; Persson, P. Acta Chem. Scand. 1990, 44, 653-675.
28. (b) Chen, T.; Hefter, G.; Marcus, Y. J. Solution Chem. 2000, 29, 201-216.
29. S = 19 or 18) for butanol (ref 12). Therefore, Lewis basicity may contribute but should not be the major factor.
30. Marcus, Y. The Properties of Solvents; Wiley: New York, 1999; p 176.
31. A certain level of flexibility is beneficial because the folded state will not be overly strained; too much flexibility, however, is detrimental to the folded conformer because the loss of entropy will be very large during folding.
32. Fluorescence resonance energy transfer (FRET) measures distance in the range of 1-10 nm, depending on the specific D-A pair utilized. Because of its nanometer-sized range, FRET has been used extensively in the characterization of conformational changes in biomolecules, such as peptides and proteins. In general, FRET is better used for measuring relative instead of absolute distances
33. (b) Selvin, P. R. Methods Enzymol. 1995, 246, 300-334.
34. (c) Lakowicz, J. R. Principles of Fluorescence Spectroscopy, 2nd ed.; Kluwer: New York, 1999; Chapter 13.
35. folding = -1.7 kcal/mol) is 3.4 kcal/mol at room temperature.
36. The two-state model seems to be reasonable for foldamers with relatively rigid repeating units, see: Prince R. B.; Saven, J. G.; Wolynes, P. G.; Moore, J. S. J. Am. Chem. Soc. 1999, 121, 3114-3121 and references therein.
37. For detailed procedures for analyzing solvent-litration curves, see: (a) Pace, C. N. Methods in Enzymology; Hirs, C. H. W., Timasheff, S. N., Eds.; Academic Press: New York, 1986; Vol. 131, pp 266-280.
38. (b) Pace, C. N. Shirley, B. A.; Thomson, J. A. In Protein Structure: A Practical Approach; Creighton, T. E., Ed.; IRL Press: New York, 1989; pp 311-330.
39. Marcus, Y. The Properties of Solvents; Wiley: New York, 1999; pp 142-154.
40. (a) Beckstein, O.; Biggin, P. C.; Sansom, M. S. P. J. Phys. Chem. B 2001, 105, 12902-12905.
41. (b) Beckstein, O.; Biggin, P. C.; Bond, P.; Bright, J. N.; Domene, C.; Grottesi, A.; Holyoake, J.; Sansom, M. S. P. FEBS Lett. 2003, 555, 85-90.