6 research outputs found
Behavior of Protein-Inspired Synthetic Random Heteropolymers
Random heteropolymers (RHPs) are an interesting class of materials useful in many theories and applications. While previous studies typically focused on simplified RHP systems, here we explore a more complex scenario inspired by highly heterogeneous molecules like proteins. Our system consists of four monomers mimicking different classes of amino acids. Using Molecular Dynamics simulations and Small-Angle X-Ray Scattering, we explore dynamical and structural features of these RHPs in solution. Our results show the RHPs assemble with heterogeneous interfaces reminiscent of protein surfaces. The polymer backbones appear frozen at room temperature on the nano- to micro-second timescale with molten globule morphology, albeit their conformational space has multiple metastable conformations for a given sequence, drawing comparison to Intrinsically Disordered Proteins. Local connectivity and chemistry are also shown to have substantial impact on polymer solvation. The work presented here indicates that RHPs share similarities with proteins to be leveraged in bio-mimetic and bio-inspired applications
Solvent Remodeling in SingleâChain Amphiphilic Heteropolymer Systems
This work demonstrates the remodeling of single-chain nanoparticles (SCNPs) upon a transition to organic solvent through molecular dynamics simulations. Methacrylate-based random heteropolymers (RHPs), assembled via transient noncovalent linkages in water, have shown promise in an assortment of applications that harness their bio-inspired properties. While their molecular behavior has been broadly characterized in aqueous environments, many newer applications include the use of organic solvent rather than bio-mimetic conditions. The polymer assemblies, typically driven by the hydrophobic effect in water, are less well understood in nonaqueous solution. Here, a specific RHP system is examined which forms compact globular morphologies in highly polar or highly nonpolar environments while adopting extended conformations in solvents of intermediate polarity. The pivotal role of electrostatic interactions between charge groups in low dielectric mediums is also observed. Finally, high temperature anneal cycles are compared to room temperature transformations to illuminate barriers to remodeling upon environmental changes
Behavior of Protein-Inspired Synthetic Random Heteropolymers
© Random heteropolymers (RHPs) are an interesting class of materials useful in many theories and applications. While previous studies typically focused on simplified RHP systems, here we explore a more complex scenario inspired by highly heterogeneous molecules like proteins. Our system consists of four monomers mimicking different classes of amino acids. Using molecular dynamics simulations and small-angle X-ray scattering, we explore dynamical and structural features of these RHPs in solution. Our results show that the RHPs assemble with heterogeneous interfaces reminiscent of protein surfaces. The polymer backbones appear frozen at room temperature on the nano- to microsecond timescale with a molten globule morphology, albeit their conformational space has multiple metastable conformations for a given sequence, drawing comparison to intrinsically disordered proteins. Local connectivity and chemistry are also shown to have a substantial impact on polymer solvation. The work presented here indicates that RHPs share similarities with proteins to be leveraged in biomimetic and bioinspired applications
Electrocatalytic Oxygen Evolution with an Immobilized TAML Activator
Iron
complexes of tetra-amido macrocyclic ligands are important
members of the suite of oxidation catalysts known as TAML activators.
TAML activators are known to be fast homogeneous water oxidation (WO)
catalysts, producing oxygen in the presence of chemical oxidants,
e.g., ceric ammonium nitrate. These homogeneous systems exhibited
low turnover numbers (TONs). Here we demonstrate immobilization on
glassy carbon and carbon paper in an ink composed of the prototype
TAML activator, carbon black, and Nafion and the subsequent use of
this composition in heterogeneous electrocatalytic WO. The immobilized
TAML system is shown to readily produce O<sub>2</sub> with much higher
TONs than the homogeneous predecessors
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Population-based heteropolymer design to mimic protein mixtures
Biological fluids, the most complex blends, have compositions that constantly vary and cannot be molecularly defined1. Despite these uncertainties, proteins fluctuate, fold, function and evolve as programmed2-4. We propose that in addition to the known monomeric sequence requirements, protein sequences encode multi-pair interactions at the segmental level to navigate random encounters5,6; synthetic heteropolymers capable of emulating such interactions can replicate how proteins behave in biological fluids individually and collectively. Here, we extracted the chemical characteristics and sequential arrangement along a protein chain at the segmental level from natural protein libraries and used the information to design heteropolymer ensembles as mixtures of disordered, partially folded and folded proteins. For each heteropolymer ensemble, the level of segmental similarity to that of natural proteins determines its ability to replicate many functions of biological fluids including assisting protein folding during translation, preserving the viability of fetal bovine serum without refrigeration, enhancing the thermal stability of proteins and behaving like synthetic cytosol under biologically relevant conditions. Molecular studies further translated protein sequence information at the segmental level into intermolecular interactions with a defined range, degree of diversity and temporal and spatial availability. This framework provides valuable guiding principles to synthetically realize protein properties, engineer bio/abiotic hybrid materials and, ultimately, realize matter-to-life transformations