Molecular Recognition by Synthetic Multifunctional Pores in Practice: Are Structural Studies Really Helpful?

Abstract

This account summarizes five years of research devoted to the development of the concept of synthetic multifunctional pores. The objective is to complement a comprehensive graphical summary of molecular recognition with a survey of structural studies on the same topic. The relevance of the latter for research focusing on creation and application of supramolecular functional materials is discussed briefly in a subjective manner.

AFM Snapshots of Synthetic Multifunctional Pores with Polyacetylene Blockers: Pseudorotaxanes and Template Effects

“…Consistent with earlier results on blockage and catalysis [12] by synthetic multifunctional pores in bilayer membranes, [4] this result . This key finding explained the absence of polyrotaxanes under the studied conditions (namely, more than two barrels per polymer; Figure 3, panels d1-d3 and c2). )…”

“…Similar guest templation has been observed in previous molecular dynamics simulations with a-helical blockers. [4] The few rotaxane motifs observed with object heights exceeding the range of 2-3 nm expected for diamond-type pseudorotaxanes 3 DR could not be interpreted convincingly (Figure 2 e). The eccentric position of the barrel with respect to the polymer was consistent with lateral complexes 3 ?L or 3 SL (Figures 2 d, 3 e).…”

“…[4] Nevertheless, structural studies on molecular recognition by synthetic multifunctional pores under conditions relevant for function indicated that pore blockage occurs by the physical insertion of the guest into the transmembrane host. [4] These findings implied the formation of inclusion complexes with small guests and of pseudorotaxanes [5][6][7][8][9][10][11] with macromolecular guests. Herein, we report on atomic force microscopy (AFM) studies in which single polyacetylene-blocked rigid-rod b-barrel pores were imaged as giant, supramacromolecular pseudorotaxanes.…”

Synthetic Multifunctional Nanoarchitecture in Lipid Bilayers: Ion Channels, Sensors, and Photosystems

“…68 To summarize, this essential line of evidence in support of the concept of rigid O-NDI rods as anion-slides begins with the confirmation of the possibility of anion-interactions with the calculation of a strongly positive quadruple moment for the NDI module. The finding that anion selective transport follows a halide VI sequence implied strong anion binding.…”

“…Although our research devoted to the creation of advanced function, 68 insights on the structural level do exist. The clear highlight among a rich and consistent collection of direct evidence are AFM snapshots obtained by Yashima, Kumaki, and co-workers that show a single polymer blocker entering and moving through a single pore 41.…”