Thermodynamic and Kinetic Stability of Synthetic Multifunctional Rigid-Rod -Barrel Pores: Evidence for Supramolecular
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- 作者：Svetlana Litvinchuk ; Guillaume Bollot ; Jiri Mareda ; Abhigyan Som ; Dawn Ronan ; Muhammad Raza Shah ; Philippe Perrottet ; Naomi Sakai ; and Stefan Matile
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：August 18, 2004
- 年：2004
- 卷：126
- 期：32
- 页码：10067 - 10075
- 全文大小：678K
- 年卷期：v.126,no.32(August 18, 2004)
- ISSN：1520-5126
文摘
The lessons learned from p-octiphenyl 
-barrel pores are applied to the rational design of syntheticmultifunctional pore 1 that is unstable but inert, two characteristics proposed to be ideal for practicalapplications. Nonlinear dependence on monomer concentration provided direct evidence that pore 1 istetrameric (n = 4.0), unstable, and "invisible," i.e., incompatible with structural studies by conventionalmethods. The long lifetime of high-conductance single pores in planar bilayers demonstrated that rigid-rod-barrel 1 is inert and large (d 
12 Å). Multifunctionality of rigid-rod -barrel 1 was confirmed by adaptableblockage of pore host 1 with representative guests in planar (8-hydroxy-1,3,6-pyrenetrisulfonate, KD = 190
M, n = 4.9) and spherical bilayers (poly-L-glutamate, KD 
105 nM, n = 1.0; adenosine triphosphate, KD= 240 M, n = 2.0) and saturation kinetics for the esterolysis of a representative substrate (8-acetoxy-1,3,6-pyrenetrisulfonate, KM = 0.6 M). The thermodynamic instability of rigid-rod -barrel 1 providedunprecedented access to experimental evidence for supramolecular catalysis (n = 3.7). Comparison ofthe obtained kcat = 0.03 min-1 with the kcat 0.18 min-1 for stable analogues gave a global KD 39 M3for supramolecular catalyst 1 with a monomer/barrel ratio 20 under experimental conditions. Thedemonstrated "invisibility" of supramolecular multifunctionality identified molecular modeling as an attractivemethod to secure otherwise elusive insights into structure. The first molecular mechanics modeling(MacroModel, MMFF94) of multifunctional rigid-rod -barrel pore hosts 1 with internal 1,3,6-pyrenetrisulfonateguests is reported.
-barrel pores are applied to the rational design of syntheticmultifunctional pore 1 that is unstable but inert, two characteristics proposed to be ideal for practicalapplications. Nonlinear dependence on monomer concentration provided direct evidence that pore 1 istetrameric (n = 4.0), unstable, and "invisible," i.e., incompatible with structural studies by conventionalmethods. The long lifetime of high-conductance single pores in planar bilayers demonstrated that rigid-rod-barrel 1 is inert and large (d 12 Å). Multifunctionality of rigid-rod -barrel 1 was confirmed by adaptableblockage of pore host 1 with representative guests in planar (8-hydroxy-1,3,6-pyrenetrisulfonate, KD = 190M, n = 4.9) and spherical bilayers (poly-L-glutamate, KD 105 nM, n = 1.0; adenosine triphosphate, KD= 240 M, n = 2.0) and saturation kinetics for the esterolysis of a representative substrate (8-acetoxy-1,3,6-pyrenetrisulfonate, KM = 0.6 M). The thermodynamic instability of rigid-rod -barrel 1 providedunprecedented access to experimental evidence for supramolecular catalysis (n = 3.7). Comparison ofthe obtained kcat = 0.03 min-1 with the kcat 0.18 min-1 for stable analogues gave a global KD 39 M3for supramolecular catalyst 1 with a monomer/barrel ratio 20 under experimental conditions. Thedemonstrated "invisibility" of supramolecular multifunctionality identified molecular modeling as an attractivemethod to secure otherwise elusive insights into structure. The first molecular mechanics modeling(MacroModel, MMFF94) of multifunctional rigid-rod -barrel pore hosts 1 with internal 1,3,6-pyrenetrisulfonateguests is reported.