A synthetic host-guest system achieves avidin-biotin affinity by overcoming enthalpy - Entropy compensation

Mikhail V. Rekharsky, Tadashi Mori, Cheng Yang, Ho Ko Young, N. Selvapalam, Hyunuk Kim, David Sobransingh, Angel E. Kaifer, Simin Liu, Lyle Isaacs, Wei Chen, Sarvin Moghaddam, Michael K. Gilson, Oon Kim, Yoshihisa Inoue

Research output: Contribution to journalArticle

406 Scopus citations

Abstract

The molecular host cucurbit[7]uril forms an extremely stable inclusion complex with the dicationic ferrocene derivative bis(trimethylammoniomethyl) ferrocene in aqueous solution. The equilibrium association constant for this host-guest pair is 3 × 1015 M-1 (Kd = 3 × 10-16 M), equivalent to that exhibited by the avidin-biotin pair. Although purely synthetic systems with larger association constants have been reported, the present one is unique because it does not rely on polyvalency. Instead, it achieves its extreme affinity by overcoming the compensatory enthalpy-entropy relationship usually observed in supramolecular complexes. Its disproportionately low entropic cost is traced to extensive host desolvation and to the rigidity of both the host and the guest.

Original languageEnglish (US)
Pages (from-to)20737-20742
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number52
DOIs
StatePublished - Dec 26 2007

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Keywords

  • Cucurbituril
  • Entropy control
  • Ferrocene derivatives
  • Host-guest complexation
  • Thermodynamics

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Rekharsky, M. V., Mori, T., Yang, C., Young, H. K., Selvapalam, N., Kim, H., Sobransingh, D., Kaifer, A. E., Liu, S., Isaacs, L., Chen, W., Moghaddam, S., Gilson, M. K., Kim, O., & Inoue, Y. (2007). A synthetic host-guest system achieves avidin-biotin affinity by overcoming enthalpy - Entropy compensation. Proceedings of the National Academy of Sciences of the United States of America, 104(52), 20737-20742. https://doi.org/10.1073/pnas.0706407105