Chemically Fueled Dissipative Self‐Assembly that Exploits Cooperative Catalysis

Abstract

In living systems, dissipative processes are driven by the endergonic hydrolysis of chemical fuels such as nucleoside triphosphates. Now, through a simple model system, a transient self‐assembled state is realized by utilizing the catalytic effect of histidine on the formation and breaking of ester bonds. First, histidine facilitates the ester bond formation, which then rapidly co‐assembles to form a self‐supporting gel. An out‐of‐equilibrium state is realized owing to the cooperative catalysis by the proximal histidines in the assembled state, driving the second pathway and resulting in disassembly to sol. Cooperative effects that use the dual role of imidazoles as nucleophile and as proton donor is utilized to achieve transient assemblies. This simple system mimics the structural journey seen in microtubule formation where the substrate GTP facilitates the non‐covalent assembly and triggers a cooperative catalytic process, leading to substrate hydrolysis and subsequent disassembly.

On the use of catalysis to bias reaction pathways in out-of-equilibrium systems

“…[23][24][25] As an illustrative example, Das and co-workers introduced a catalytic histidine moiety in a self-supporting hydrogel, exhibiting fuel-driven transient stability and cooperative catalysis. 26 The transient hydrogel was generated by esterication of the carboxylic end group of lipid functionalized histidine amphiphile precursors using a watersoluble carbodiimide as chemical fuel in combination with a p-nitrophenol nucleophile. A cooperative catalytic effect was realized by the proximity of the imidazole group of histidine, boosting the ester hydrolysis rate in the assembled state and consequently the disassembly of the gel state.…”

“…Nonetheless, several examples of articial non-equilibrium systems with enzyme, transition metal, organocatalysis and acid catalysis have been developed in recent years. [15][16][17][18][19][20][21][23][24][25][26]40,41 The majority of these examples exploit enzyme catalysis to regulate maximum conversion and lifetime. Only a small number of transition metal and organocatalytically regulated out-of-equilibrium systems is reported to date.…”

“…Moreover, coupling catalysis to a dissipative CRN containing assembling products could give rise to unusual assembly behaviour and feedback. [26][27][28]44 Here, instead of using enzymes, with limited operational stability and high specicity, it would be recommended to start exploring small molecules and metal catalysts. This way organocatalysis in combination with metal catalysis in non-natural systems can play similar roles as enzymes in nature and provide new systems with a high degree of control and an adaptive character.…”

Synthesis of Complex Molecular Systems—The Foreseen Role of Organic Chemists

“…Especially the group of Ulijn pioneered the biocatalytic synthesis of peptidic gelators. 76 − 78 The group showed among others that enzymes are versatile catalysts to form and hydrolyze carboxylic acid esters, 76 , 79 amides, 77 , 78 and phosphoesters 80 − 85 ( Scheme 4 a–c). The power of redox active enzymes has been harvested by Besenius and co-workers.…”

“… For examples where these transformations were applied to supramolecular building blocks, see (a) refs ( 76 , 79 ); (b) refs ( 77 , 78 ); (c) refs ( 80 − 85 ); (d) ref ( 86 ); (e) ref ( 66 ). …”