Efficient encapsulation of proteins with random copolymers

Abstract

Membraneless organelles are aggregates of disordered proteins that form spontaneously to promote specific cellular functions in vivo. The possibility of synthesizing membraneless organelles out of cells will therefore enable fabrication of protein-based materials with functions inherent to biological matter. Since random copolymers contain various compositions and sequences of solvophobic and solvophilic groups, they are expected to function in nonbiological media similarly to a set of disordered proteins in membraneless organelles. Interestingly, the internal environment of these organelles has been noted to behave more like an organic solvent than like water. Therefore, an adsorbed layer of random copolymers that mimics the function of disordered proteins could, in principle, protect and enhance the proteins' enzymatic activity even in organic solvents, which are ideal when the products and/or the reactants have limited solubility in aqueous media. Here, we demonstrate via multiscale simulations that random copolymers efficiently incorporate proteins into different solvents with the potential to optimize their enzymatic activity. We investigate the key factors that govern the ability of random copolymers to encapsulate proteins, including the adsorption energy, copolymer average composition, and solvent selectivity. The adsorbed polymer chains have remarkably similar sequences, indicating that the proteins are able to select certain sequences that best reduce their exposure to the solvent. We also find that the protein surface coverage decreases when the fluctuation in the average distance between the protein adsorption sites increases. The results herein set the stage for computational design of random copolymers for stabilizing and delivering proteins across multiple media.

Water follows polar and nonpolar protein surface domains

“…A quantitative understanding of protein surface domains is a prerequisite for designing ligands with optimal binding affinity. The coexistence of small polar and nonpolar domains has been observed for a variety of proteins (17,(20)(21)(22), and is probably a common feature (with possible exceptions of membrane proteins, where belt-shaped hydrophobic surface domains are expected). Previously, using our increased knowledge of protein surface domains, we were able to design random heteropolymers for preserving active enzymes in nonnative environments (17).…”

“…See the review (19) and references therein. These properties are influenced and, in many cases, determined by the polar and nonpolar domains on protein surfaces, which are a few angstroms in length (17,(20)(21)(22). Unfortunately, the existing experimental techniques are currently limited in their capability to quantify such local hydration on a protein surface (23)(24)(25).…”

Mechanistic Insights into Statistical Co‐Assembly of Metal Complexes

“…Statistical or random copolymerization plays a key role in multiple biological processes and is a commonly used strategy to enhance the physical properties of technological materials in general . In such polymers, the monomer residues are distributed within uneven sequences along the (covalent) molecular chain .…”

Protein‐inorganic calcium‐phosphate supraparticles as a robust platform for enzyme co‐immobilization

“…Enzymes may be encapsulated, which can increase biocatalyst lifetime by mitigating unfolding events. Encapsulation methods are often broadly applicable to many enzymes (Espanol, Casals, Lamtahri, Valderas, & Ginebra, 2012; Fujita et al, 2012; Gupta et al, 2016; Nguyen, Qiao, & Olvera de la Cruz, 2018). However, encapsulation can inhibit enzyme motion or diffusion of substrate, product or cofactors, leading to a decrease in catalytic efficiency (Fu & Kao, 2010; Macha et al, 2019; Shakya & Nandakumar, 2018).…”