Molecular Dynamics Simulations Reveal a Dielectric-Responsive Coronal Structure in Protein–Polymer Surfactant Hybrid Nanoconstructs

Abstract

Solvent-free liquid proteins are a new class of thermally stable hybrid bionanomaterials that are produced by extensive lyophilization of aqueous solutions of protein-polymer surfactant nanoconjugates followed by thermal annealing. The hybrid constructs, which consist of a globular protein core surrounded by a monolayer of electrostatically coupled polymer surfactant molecules, exhibit nativelike structure, function, and backbone dynamics over a large temperature range. Despite the key importance of the polymer surfactant shell, very little is known about the atomistic structure of the corona and how it influences the phase behavior and properties of these novel nanoscale objects. Here we present molecular dynamics simulations of protein-polymer surfactant nanoconjugates consisting of globular cores of myoglobin or lysozyme and demonstrate that the derived structural parameters are highly consistent with experimental values. We show that the coronal layer structure is responsive to the dielectric constant of the medium and that the mobility of the polymer surfactant molecules is significantly hindered in the solvent-free state, providing a basis for the origins of retained protein dynamics in these novel biofluids. Taken together, our results suggest that the extension of molecular dynamics simulations to hybrid nanoscale objects could be of generic value in diverse areas of soft matter chemistry, bioinspired engineering, and biomolecular nanotechnology.

Tandem catalysis in multicomponent solvent-free biofluids

“…The compacted and patchy coverage of a supercharged enzyme in aqueous solution is in line with previous reports on polymer-tethered lysozyme and myoglobin studied by a combination of small-angle neutron scattering and molecular dynamics simulations. 28 We further confirmed its correspondence with the cationized protein's surface charge distribution by performing continuum electrostatics calculations via the PDB2PQR web server 29,30 to map the electrostatic potential of the supercharged protein surface (Fig. S3 †).…”

Insight into the Structure and Activity of Surface‐Engineered Lipase Biofluids

“…In the lyophilized solvent‐free state, the role of the polymer surfactant coating in maintaining enzyme structure and activity is even more pronounced . Genetic engineering allowed BsLA to be sterically stabilised with more polymer surfactants in the corona (Tables S1 and S2).…”

Liquefaction of Biopolymers: Solvent-free Liquids and Liquid Crystals from Nucleic Acids and Proteins

“…Molecular dynamics simulations allow a yet deeper insight into the atomistic structure suggesting that the mobility of the surfactant molecules is impaired and thus responsible for the retention and observability of the intermediate unfolding state. 56 In addition, anisotropic glucose oxidase–surfactant complexes can be synthesized exhibiting liquid, LC, and solid phase features while retaining the secondary structure. 57 As the conformational transition temperature of the enzyme correlates with the LC to liquid transition, it is likely that the shape anisotropy of the protein–surfactant building blocks plays a pivotal role in the formation of ordered structures of the complex.…”