Polymer Modification of Lipases, Substrate Interactions, and Potential Inhibition

Abstract

An industrially important enzyme, Candida antarctica lipase B (CalB), was modified with a range of functional polymers including hydrophilic, hydrophobic, anionic, and cationic character using a “grafting to” approach. We determined the impact of polymer chain length on CalB activity by synthesizing biohybrids of CalB with each polymer at three different chain lengths, using reversible addition-fragmentation chain transfer (RAFT) polymerization. The activity of CalB in both aqueous and aqueous-organic media mixtures was significantly enhanced for acrylamide (Am) and N,N-dimethyl acrylamide (DMAm) conjugates, with activity remaining approximately constant in 25 and 50% ethanol solvent systems. Interestingly, the activity of N,N-dimethylaminopropyl-acrylamide (DMAPA) conjugates increased gradually with increasing organic solvent content in the system. Contrary to other literature reports, our study showed significantly diminished activity for hydrophobic polymer-protein conjugates. Functional thermal stability assays also displayed a considerable enhancement of retained activity of Am, DMAm, and DMAPA conjugates compared to the native CalB enzyme. Thus, this study provides an insight into possible advances in lipase production, which can lead to new improved lipase bioconjugates with increased activity and stability.

Conserved Protein–Polymer Interactions across Structurally Diverse Polymers Underlie Alterations to Protein Thermal Unfolding

“…POEGMA and PDMA are among the most promising PEG alternatives in bioconjugation. − The documented physical properties of the polymers provide a basis for testing properties of their corresponding protein conjugates. Both PDMA and POEGMA are neutral polymers, but they exhibit significantly different architectures and hydrophobiticites (Figure ).…”

Polymer modification of SARS-CoV-2 spike protein impacts its ability to bind key receptor

“…RAFT was used with the chain transfer agent 2-(((ethylthio)-carbonothioyl)thio propionic acid (PAETC) ( Scheme 1 a & 1c). [47] , [48] Initially, polymers with a targeted degree of polymerization of 25 units were prepared with differing hydrophilicity i.e. , hydrophilic N,N - dimethyl acrylamide (DMAm) and hydrophobic N -isopropyl acrylamide (NIPAm).…”

“…Generally, hydrophilic polymers tend to form noncovalent hydrogen bond interactions with amino acid residues at the protein surface while hydrophobic polymers tend to reduce the solubility of protein. [47] , [48] Additionally, to investigate the impact of charge properties of polymers on bioconjugate performance, cationic N,N -dimethyl aminopropyl acrylamide (DMAPA) and anionic 2-acrylamido-2-methylpropane sulfonic acid (AMPSA) monomers were also incorporated into the DMAm polymers in a 1:1 ratio with a targeted degree of polymerization of 25. The ionizable group containing polymers are predicted to strongly interact with the protein through electrostatics, with a smaller tendency to form hydrogen bonds with the protein.…”

“…Previous studies indicate that anionic polymers tend to unfold protein structure, which agrees with this observation. [47] , [52]

Figure 1 Percent relative ACE2 interaction of HRP linked spike RBD protein in presence of DMAm DP25, DMAm DP10, DMAm DP5, DMAm DP12.5-DMAPA DP12.5, DMAm DP12.5-AMPSA DP12.5 and NIPAm DP25 polymers. The percent relative ACE2 interaction is determined as .

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Concentration Effect over Thermoresponse Derived from Organometallic Compounds of Functionalized Poly(N-isopropylacrylamide-co-dopamine Methacrylamide)

“…The generation of smart materials is a valuable way to respond to a part of industrial demand as they can improve the efficiency of some processes, reduce the consumption of energy, and are biodegradable in some cases where biodegradable monomers are involved as well [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Many efforts focus on the preparation and characterization of these materials, but the composites and functionalized polymers are growing as those can provide specific and modulated properties.…”