Non-Equilibrium Generation of Catalytic Supramolecular Polymers of Pre-RNA Nucleobases

<p>Bioenergetics played critical roles for the chemical emergence of life where available energy resources drove the generation of primitive polymers and fueled early metabolism. Further, apart from information storage, the catalytic roles of primitive nucleic acid fragments have also been argued to be important for biopolymer evolution. Herein, we have demonstrated the non-equilibrium generation of catalytic supramolecular polymers of a possible proto-RNA building block (melamine) driven by a thermodynamically activated ester of low molecular weight. We utilized reversible covalent linkage to install a catalytic imidazole moiety in the polymer backbone. This resulted in energy dissipation via hydrolysis of the substrate predominantly from the assembled state and subsequent disassembly, thus installing kinetic asymmetry in the energy consumption cycle. Non-catalytic analogues led to kinetically stable polymers while inactivated substrates were unable to drive the polymerization. The non-equilibrium polymers of the pre-RNA bases were capable to spatiotemporally bind to a model cofactor. Notably, presence of an exogenous aromatic base augmented the stability of the polymers, reminiscent to what the molecular midwives did during early evolution. </p>

Non-Equilibrium Generation of Catalytic Supramolecular Polymers of Pre-RNA Nucleobases

<p>Bioenergetics played critical roles for the chemical emergence of life where available energy resources drove the generation of primitive polymers and fueled early metabolism. Further, apart from information storage, the catalytic roles of primitive nucleic acid fragments have also been argued to be important for biopolymer evolution. Herein, we have demonstrated the non-equilibrium generation of catalytic supramolecular polymers of a possible proto-RNA building block (melamine) driven by a thermodynamically activated ester of low molecular weight. We utilized reversible covalent linkage to install a catalytic imidazole moiety in the polymer backbone. This resulted in energy dissipation via hydrolysis of the substrate predominantly from the assembled state and subsequent disassembly, thus installing kinetic asymmetry in the energy consumption cycle. Non-catalytic analogues led to kinetically stable polymers while inactivated substrates were unable to drive the polymerization. The non-equilibrium polymers of the pre-RNA bases were capable to spatiotemporally bind to a model cofactor. Notably, presence of an exogenous aromatic base augmented the stability of the polymers, reminiscent to what the molecular midwives did during early evolution. </p>

Active Brownian particles: mapping to equilibrium polymers and exact computation of moments

A polymer-mapping of active Brownian particle (ABP)-trajectories, and exact calculation of the moments of dynamical variables provide insights into the mechanical crossovers in polymers with length, and related dynamical crossovers in ABP-motion.

Effect of the Strength of Attraction Between Nanoparticles on Wormlike Micelle- Nanoparticle System

The nanoparticle-Equilibrium polymer (or Wormlike micellar) system shows morphological changes from percolating network-like structures to non-percolating clusters with a change in the minimum approaching distance (EVP-excluded volume parameter) between nanoparticles and the matrix of equilibrium polymers. The shape anisotropy of nanoparticle clusters can be controlled by changing the polymer density. In this paper, the synergistic self-assembly of nanoparticles inside equilibrium polymeric matrix (or Wormlike micellar matrix) is investigated with respect to the change in the strength of attractive interaction between nanoparticles. A shift in the point of morphological transformation of the system to lower values of EVP as a result of a decrease in the strength of the attractive nanoparticle interaction is reported. We show that the absence of the attractive interaction between nanoparticles leads to the low packing of nanoparticle structures, but does not change the morphological behavior of the system. We also report the formation of the system spanning sheet-like arrangement of nanoparticles which are arranged in alternate layers of matrix polymers and nanoparticles.

Exquisite regulation of supramolecular equilibrium polymers in water: chain stoppers control length, polydispersity and viscoelasticity

Positively charged molecules with planar surfaces control the length of supramolecular polymers formed by 2,4,6-triaminopyrimidine and a modified cyanuric acid.

Integration of molecular machines into supramolecular materials: actuation between equilibrium polymers and crystal-like gels

A phase transition between equilibrium polymer solutions and crystal-like gels can be controlled by the pH nano-actuation of the mechanical bond of a rotaxane-based supramolecular polymer.