Supramolecular Assembly of a Molecularly Engineered Protein and Polymer

• Published in: Chemistry : a European journal Vol. 25; no. 44; pp. 10464 - 10471
• Main Authors: Sikder, Amrita, Ray, Debes, Aswal, Vinod K., Ghosh, Suhrit
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 06.08.2019; Wiley Subscription Services, Inc
• Subjects: Assembly; Biomolecules; Bovine serum albumin; Chemistry; Chemistry, Multidisciplinary; Collapse; Conjugates; conjugation; Enzymatic activity; Heterogeneity; hydrogen bonds; Isopropylacrylamide; Micelles; Molecular weight; Physical Sciences; Polymers; Protein denaturation; Proteins; Science & Technology; self-assembly; Serum albumin; Structural hierarchy; Thermal denaturation; Thermal stability; self-assembly; DYES; VESICLES; proteins; DNA; FABRICATION; polymers; conjugation; hydrogen bonds
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201901844

Programmable assembly of biomolecules is a fast growing research area that aims to emulate nature's elegance in creating numerous hierarchical self‐assembled structures, which are responsible for unimaginably difficult biological functions. Protein assembly is a particularly challenging task, owing to their structural diversity, conformational heterogeneity, and high molecular weight. This article reveals the ability of a supramolecular structure‐directing unit (SSDU) to regulate the entropically favourable supramolecular assembly of a covalently conjugated protein (bovine serum albumin (BSA)) to produce well‐defined protein‐decorated micelles with remarkably high thermal stability, suppression of the thermal denaturation of the protein, and retention of enzymatic activity. Furthermore, a SSDU‐appended thermo‐responsive poly(N‐isopropylacrylamide) (PNIPAM) co‐assembles with the SSDU–BSA conjugate because, in both cases, assembly was primarily driven by specific molecular recognition between the SSDUs. However, the resulting supramolecular protein–polymer conjugate exhibits distinctly different polymersome structure to that of the micellar particle produced by the protein‐SSDU conjugate. In this case, the enzymatic activity can be significantly suppressed above the lower critical solution temperature of supramolecularly conjugated PNIPAM, possibly due to collapse of the de‐solvated polymer chains on the protein surface. Taking directions: Specific directional molecular interactions among appended supramolecular structure‐directing units (SSDUs) lead to an entropically driven, remarkably stable, protein assembly (see figure). Supramolecular bioconjugation with the SSDU‐appended polymer generates distinctly different polymersome structures with the stimuli‐responsive enzymatic activity of the protein.