Enzyme-assisted self-assembly under thermodynamic control

Abstract

The production of functional molecular architectures through self-assembly is commonplace in biology, but despite advances, it is still a major challenge to achieve similar complexity in the laboratory. Self-assembled structures that are reproducible and virtually defect free are of interest for applications in three-dimensional cell culture, templating, biosensing and supramolecular electronics. Here, we report the use of reversible enzyme-catalysed reactions to drive self-assembly. In this approach, the self-assembly of aromatic short peptide derivatives provides a driving force that enables a protease enzyme to produce building blocks in a reversible and spatially confined manner. We demonstrate that this system combines three features: (i) self-correction--fully reversible self-assembly under thermodynamic control; (ii) component-selection--the ability to amplify the most stable molecular self-assembly structures in dynamic combinatorial libraries; and (iii) spatiotemporal confinement of nucleation and structure growth. Enzyme-assisted self-assembly therefore provides control in bottom-up fabrication of nanomaterials that could ultimately lead to functional nanostructures with enhanced complexities and fewer defects.

Catalysis of Supramolecular Hydrogelation

“…We now added a fifth design principle 25 : 5) use a catalyst to enhance the rate of the final bond forming reaction leading to formation of the assembling molecule. To various degrees, these principles have been applied to controlling self-assembly through enzymatic catalysis 26,27,28,29,30,31 and synthetic catalysis 32,33 . Figure 1.…”

Chemoenzymatic Synthesis of Polypeptides for Use as Functional and Structural Materials

“…Although thermodynamic control of the equilibrium for enzymatic peptide formation can be applied during the synthesis of small peptides or fragment coupling, it is insufficient for polypeptide preparation resulting from sequential steps of aminolysis. [35][36][37] The aminolysis reaction can be kinetically accelerated by using moderately activated acyl donors (generally, amino acid esters). The ester group of amino acid derivatives reacts rapidly with catalytic cysteine or serine to produce an activated intermediate, followed by aminolysis, which creates an amide bond.…”

Self-Assembled Peptides: Characterisation and In Vivo Response

“…Once introduced to the tissue, the peptide assemblies interact with the implanted cells, directly contacting and supporting the host tissue, or, more typically, rely on endogenous cells migrating into the scaffold to promote repair form nanostructured fibrous materials. Here, we define molecular self-assembly as the spontaneous organisation of molecules under thermodynamic and kinetic conditions into stable and structurally welldefined arrangements [30,31]. This process is driven/governed by a range of numerous weak non-covalent interactions.…”

“…A wide range of techniques have been used to characterise these systems spectroscopically, optically and mechanically at each stage of the assembly process [23,30,32,36,37]. Individual subunit interactions have been characterised by UV-vis spectroscopy, in which the emission wavelength changes during aggregate formation.…”

“…One way reactions allow variable stiffness from identical peptides by altering the enzyme concentration and therefore the rate of formation, which has been exploited to control cell fate [26,51]. Conversely, reversible mechanisms under thermodynamically controlled conditions result in identical gels, as they achieve more ordered interactions via component selection [30,52]. However, such systems are also useful for tissue engineering as they can be employed to incorporate whole proteins for in vivo delivery [23,40].…”