Abstract
Biochemical acyl transfer cascades, such as those initiated by the adenylation of carboxylic acids, are central to various biological processes, including protein synthesis and fatty acid metabolism. Designing aqueous cascades outside of biology remains challenging due to the need to control multiple, sequential reactions in a single pot and manage the stability of reactive intermediates. Herein, we developed abiotic cascades using aminoacyl phosphate esters, the synthetic counterparts of biological aminoacyl adenylates, to drive sequential chemical reactions and self-assembly in a single pot. We demonstrated that the structural elements of amino acid side chains (aromatic versus aliphatic) significantly influence the reactivity and half-lives of aminoacyl phosphate esters, ranging from hours to days. This behavior, in turn, affects the number of couplings we can achieve in the network and the self-assembly propensity of activated intermediate structures. The cascades are constructed using bifunctional peptide substrates featuring side chain nucleophiles. Specifically, aromatic amino acids facilitate the formation of transient thioesters, which preorganized into spherical aggregates and further couple into chimeric assemblies composed of esters and thioesters. In contrast, aliphatic amino acids, which lack the ability to form such structures, predominantly lead to hydrolysis, bypassing elongation after thioester formation. Additionally, in mixtures containing multiple aminoacyl phosphate esters and peptide substrates, we achieved selective product formation by following a distinct pathway that favors elongation through self-assembly. By coupling chemical reactions using molecules with varying reactivity timescales, we can drive multiple reaction clocks with distinct lifetimes and self-assembly dynamics, thereby facilitating precise temporal and structural regulation.
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The Supporting Information is available free of charge on the ACS Publications website. The Supporting Information contains a Materials and Methods description and additional UPLC chromatograms, LC-MS analyses, kinetic profiles, reaction pathways, tables with chemical structures, Transmission Electron Microscopy images and turbidity measurements.
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