Globular Polymer Grafts Require a Critical Size for Efficient Molecular Sieving of Enzyme Substrates

McNelles, Stuart A.; Marando, Victoria M.; Adronov, Alex

doi:10.1002/anie.201902864

Cited by 7 publications

(16 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ligand binding rate depended strongly on the ligand size and grafting density, but not on ligand shape or polymer chain length. In another example, Adronov et al reported CT-polyester dendrimer conjugates with increasing numbers of generations finding that 7 generations were needed for effective sieving . Grafted-from protein–polymer conjugates have not yet been FDA-approved.…”

Section: Protein–polymer Conjugatesmentioning

confidence: 99%

Atom Transfer Radical Polymerization for Biorelated Hybrid Materials

et al. 2019

View full text Add to dashboard Cite

Proteins, nucleic acids, lipid vesicles, and carbohydrates are the major classes of biomacromolecules that function to sustain life. Biology also uses post-translation modification to increase the diversity and functionality of these materials, which has inspired attaching various other types of polymers to biomacromolecules. These polymers can be naturally (carbohydrates and biomimetic polymers) or synthetically derived and have unique properties with tunable architectures. Polymers are either grafted-to or grown-from the biomacromolecule's surface, and characteristics including polymer molar mass, grafting density, and degree of branching can be controlled by changing reaction stoichiometries. The resultant conjugated products display a chimerism of properties such as polymer-induced enhancement in stability with maintained bioactivity, and while polymers are most often conjugated to proteins, they are starting to be attached to nucleic acids and lipid membranes (cells) as well. The fundamental studies with protein−polymer conjugates have improved our synthetic approaches, characterization techniques, and understanding of structure−function relationships that will lay the groundwork for creating new conjugated biomacromolecular products which could lead to breakthroughs in genetic and tissue engineering.

show abstract

Section: Protein–polymer Conjugatesmentioning

confidence: 99%

Atom Transfer Radical Polymerization for Biorelated Hybrid Materials

et al. 2019

View full text Add to dashboard Cite

show abstract

“…It is worth noting that the R g for aprotinin is only 1.1 nm. While it has been demonstrated that increasing polymer grafting density or attachment of several generation dendrimers can reduce permeation of smaller molecules (casein) and hinder permeation of larger molecules (BSA), , the data provided herein provide the first evidence, to our knowledge, that rationally designed nanoarmored protein–polymer conjugates can prevent protein–protein interactions while preserving biological activity.…”

Section: Discussionmentioning

confidence: 72%

Molecular Dynamics-Guided Design of a Functional Protein–ATRP Conjugate That Eliminates Protein–Protein Interactions

et al. 2021

View full text Add to dashboard Cite

Even the most advanced protein−polymer conjugate therapeutics do not eliminate antibody−protein and receptor−protein recognition. Next-generation bioconjugate drugs will need to replace stochastic selection with rational design to select desirable levels of protein−protein interaction while retaining function. The "Holy Grail" for rational design would be to generate functional enzymes that are fully catalytic with small molecule substrates while eliminating interaction between the protein surface and larger molecules. Using chymotrypsin, an important enzyme that is used to treat pancreatic insufficiency, we have designed a series of molecular chimeras with varied grafting densities and shapes. Guided by molecular dynamic simulations and next-generation molecular chimera characterization with asymmetric flow field-flow fractionation chromatography, we grew linear, branched, and comb-shaped architectures from the surface of the protein by atom-transfer radical polymerization. Comb-shaped polymers, grafted from the surface of chymotrypsin, completely prevented enzyme inhibition with protein inhibitors without sacrificing the ability of the enzyme to catalyze the hydrolysis of a peptide substrate. Asymmetric flow field-flow fractionation coupled with multiangle laser light scattering including dynamic light scattering showed that nanoarmor designed with comb-shaped polymers was particularly compact and spherical. The polymer structure significantly increased protein stability and reduced protein−protein interactions. Atomistic molecular dynamic simulations predicted that a dense nanoarmor with long-armed comb-shaped polymer would act as an almost perfect molecular sieve to filter large ligands from substrates. Surprisingly, a conjugate that was composed of 99% polymer was needed before the elimination of protein−protein interactions.

show abstract

“…Having prepared the PEGylated dendrons with reactive DBCO units at the core, we proceeded to graft these structures to the surface of α-CT, following previously established protocols . Treatment of the 14 surface lysine residues of α-CT with 2-azidoacetic acid introduced the required azide functionalities on the enzyme to allow SPAAC coupling with the dendrons while maintaining aqueous solubility.…”

Section: Resultsmentioning

confidence: 99%

“…The above work infers that optimizing sieving activity on a protein conjugate is a multifaceted process that cannot simply be achieved through modifying grafting density, architecture, or molecular weight alone. Using a different approach, our group has recently explored molecular sieving in dendritic polymer conjugates, specifically high-generation dendrimer-chymotrypsin (CT) hybrids . Dendrimers offer excellent control over dispersity and morphology, which we rationalized would ensure a uniform monolayer when grafted onto the enzyme.…”

Section: Introductionmentioning

confidence: 99%

“…To address these shortcomings, we combined the synthetic ease of using linear polymers with the advantages of dendritic architectures by utilizing low-to-medium generation linear–dendritic hybrid structures (Figure ). This approach allows the use of easily synthesized lower generation dendrons that are surface functionalized with linear PEG chains to achieve a dense coating on the enzyme surface. − The linear–dendritic regime can also mitigate poor sieving associated with the lower internal density observed in lower generation dendrons . Linear PEG is a promising candidate polymer to be introduced at the dendron periphery as it has previously been shown to prevent cell-adhesion and repel protein adsorption, ,− but has yet to be used widely in the context of molecular sieving. , While it has been found that introduction of multiple PEG chains directly on the protein surface can result in significant loss of activity, ,,− we hypothesized that a dendritic spacer could serve as a buffer against PEG-protein self-association or blockage of the active site. , Therefore, in a continued effort to explore optimal architectures for molecular sieving, we herein present a series of α-CT conjugates with bis-MPA dendrons of generations (G) 3–5 with three different PEG chain lengths at their periphery ( M w = 350 Da, 1 kDa, 2 kDa, n = 8, 22, 45, respectively).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Molecular Sieving with PEGylated Dendron-Protein Conjugates

et al. 2023

Self Cite

View full text Add to dashboard Cite

A series of generation 3−5 dendrons based on a bis(2,2hydroxymethylpropionic acid) (bis-MPA) scaffold bearing three respective lengths of linear poly(ethylene glycol) at their periphery and a dibenzocyclooctyne unit at their core was prepared. These dendrons were appended to the surface of azide-decorated α-chymotrypsin (α-CT) via strain-promoted azide−alkyne cycloaddition to yield a library of dendron-protein conjugates. These conjugates were characterized by FT-IR and NMR spectroscopy and were imaged using cryo-electron microscopy. The activity of the PEGylated α-CT-dendron conjugates was investigated using a small molecule (benzoyl-L-tyrosine p-nitroanilide) as well as different proteins of different sizes and crystallinities (casein and bovine serum albumin) as substrates. It was found that the activity of the conjugates toward the small molecule was largely retained, while the activity toward the proteins was significantly diminished. Furthermore, the results indicate that for most of the conjugates the PEG length had a more pronounced impact on enzyme activity than the dendron generation. Overall, the highest sieving ratios were found for α-CT-dendron conjugates decorated with G3-PEG 2000 , G4-PEG 2000 , and G5-PEG 1000 , with the latter two structures offering the best combination of sieving ratio and small molecule activity.

show abstract

Globular Polymer Grafts Require a Critical Size for Efficient Molecular Sieving of Enzyme Substrates

Cited by 7 publications

References 56 publications

Atom Transfer Radical Polymerization for Biorelated Hybrid Materials

Atom Transfer Radical Polymerization for Biorelated Hybrid Materials

Molecular Dynamics-Guided Design of a Functional Protein–ATRP Conjugate That Eliminates Protein–Protein Interactions

Molecular Sieving with PEGylated Dendron-Protein Conjugates

Contact Info

Product

Resources

About