Exploring the emergence of complexity using synthetic replicators

Abstract

A significant number of synthetic systems capable of replicating themselves or entities that are complementary to themselves have appeared in the last 30 years. Building on an understanding of the operation of synthetic replicators in isolation, this field has progressed to examples where catalytic relationships between replicators within the same network and the extant reaction conditions play a role in driving phenomena at the level of the whole system. Systems chemistry has played a pivotal role in the attempts to understand the origin of biological complexity by exploiting the power of synthetic chemistry, in conjunction with the molecular recognition toolkit pioneered by the field of supramolecular chemistry, thereby permitting the bottom-up engineering of increasingly complex reaction networks from simple building blocks. This review describes the advances facilitated by the systems chemistry approach in relating the expression of complex and emergent behaviour in networks of replicators with the connectivity and catalytic relationships inherent within them. These systems, examined within well-stirred batch reactors, represent conceptual and practical frameworks that can then be translated to conditions that permit replicating systems to overcome the fundamental limits imposed on selection processes in networks operating under closed conditions. This shift away from traditional spatially homogeneous reactors towards dynamic and non-equilibrium conditions, such as those provided by reaction-diffusion reaction formats, constitutes a key change that mimics environments within cellular systems, which possess obvious compartmentalisation and inhomogeneity.

Can Life Emerge from Synthetic Polymers?

“…dynamic combinatorial libraries, oscillating reactions, autocatalytic compounds) . For instance, several minimal self‐replicating systems (see section 4.3) but also more complex networks of synthetic replicators have been studied . However, in most cases, these systems end up in thermodynamically or kinetically‐trapped products.…”

“…[56] For instance, several minimal self-replicating systems (see section 4.3) but also more complex networks of synthetic replicators have been studied. [57] However, in most cases, these systems end up in thermodynamically or kinetically-trapped products. An elegant example of chemicallyfuelled self-replicating system was reported earlier this year by Fletcher and coworkers.…”

Tuning the Outcome of Enzyme‐Mediated Dynamic Cyclodextrin Libraries to Enhance Template Effects

“…Dynamic combinatorial chemistry has evolved into a powerful tool to explore molecular self‐assembly and systems chemistry behavior, and to identify macrocyclic hosts for small molecules or ligands for biomacromolecules . Dynamic covalent reactions have been exploited to develop smart materials, to generate self‐replicating systems, and have enabled access to complicated macrocycles such as (hemi)cucurbit[ n ]urils, biotin[6]urils, cryptates and larger nano‐rings . Significant effort has been exerted to develop synthetic dynamic systems that mimic biological dynamic systems.…”

The Influence of Modularity, Seeding, and Product Inhibition on Peptide Autocatalytic Network Dynamics

“…The origin of life inevitably involved the selection of functional molecules and self‐organized molecular networks, made possible through the reliable replication of either individual molecules or entire sets of molecules. Minimal molecular self‐replication has been demonstrated using synthetic nucleic acid and peptide entities, and subsequently the formation of small replication networks has been realized experimentally …”

“…Minimal molecular selfreplication has been demonstrated using synthetic nucleic acid and peptide entities, [1][2][3][4][5][6] and subsequently the formation of small replication networks has been realized experimentally. [7][8][9] One of the few successful examples of the latter involves a set of nine peptide molecules that mutually catalyze each other's formation from shorter peptide fragments, such that the set as a whole is self-reproducing. [10] However, such experiments are often difficult to perform in the laboratory.…”