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Peptides displayed as high density brush polymers resist proteolysis and retain bioactivity.

Blum AP, Kammeyer JK, Yin J, Crystal DT, Rush AM, Gilson MK, Gianneschi NC - J. Am. Chem. Soc. (2014)

Bottom Line: We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers.The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells.The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry & Biochemistry, ‡Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego , La Jolla, California 92093, United States.

ABSTRACT
We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers. The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells. The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease. Finally, we demonstrate that the proteolytic susceptibility of peptide brush polymers can be tuned by adjusting the density of the polymer brush and offer in silico models to rationalize this finding. We contend that this strategy offers a plausible method of preparing peptides for in vivo use, where rapid digestion by proteases has traditionally restricted their utility.

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Plots correlating the number-average molecular weight (Mn) with the initial monomer–to-catalystratio ([M0/I0] for the polymerization of theArg8 monomer (A) and the Tat monomer (B). Linear fits are indicativeof a living polymerization. For both monomers, propagation ceasedafter the polymerization of ∼9 monomers.
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fig2: Plots correlating the number-average molecular weight (Mn) with the initial monomer–to-catalystratio ([M0/I0] for the polymerization of theArg8 monomer (A) and the Tat monomer (B). Linear fits are indicativeof a living polymerization. For both monomers, propagation ceasedafter the polymerization of ∼9 monomers.

Mentions: Given the complexity of theTat and Arg8 peptide-containing polymers(i.e., multiple charged and nucleophilic side chains), we investigatedwhether ROMP of these materials proceeds in a living fashion, in orderto ensure that well-defined and well-ordered structures, devoid ofcross-metathesis or premature termination, could regularly be accessedby this strategy. Confirming the living nature of the polymerization,a plot of Mn (obtained by SEC-MALS) vs[M]0/[I]0 for the Arg8 monomer yields a linearfit for [M]0/[I]0 less than 9 (Figure 2A and Table 2). At larger[M]0/[I]0 ratios, propagation ceased, presumablydue to steric hindrance encountered from assembling multiple copiesof the long, side-chain protected peptide sequence, whose molecularweight as a monomer is 3.5 kDa. A similar plot was obtained from datagathered for polymerization of the Tat polymer, collected by staticlight scattering (SLS) in a cuvette (Figure 2B and Table 2). Therefore, we conclude thatboth CPP monomers are polymerized in a living fashion to a DP of <9,despite the complexity and functionality of their side chains, makingthis an exceptionally convenient strategy for predictably generatingpolymeric architectures from peptide monomers.


Peptides displayed as high density brush polymers resist proteolysis and retain bioactivity.

Blum AP, Kammeyer JK, Yin J, Crystal DT, Rush AM, Gilson MK, Gianneschi NC - J. Am. Chem. Soc. (2014)

Plots correlating the number-average molecular weight (Mn) with the initial monomer–to-catalystratio ([M0/I0] for the polymerization of theArg8 monomer (A) and the Tat monomer (B). Linear fits are indicativeof a living polymerization. For both monomers, propagation ceasedafter the polymerization of ∼9 monomers.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4227725&req=5

fig2: Plots correlating the number-average molecular weight (Mn) with the initial monomer–to-catalystratio ([M0/I0] for the polymerization of theArg8 monomer (A) and the Tat monomer (B). Linear fits are indicativeof a living polymerization. For both monomers, propagation ceasedafter the polymerization of ∼9 monomers.
Mentions: Given the complexity of theTat and Arg8 peptide-containing polymers(i.e., multiple charged and nucleophilic side chains), we investigatedwhether ROMP of these materials proceeds in a living fashion, in orderto ensure that well-defined and well-ordered structures, devoid ofcross-metathesis or premature termination, could regularly be accessedby this strategy. Confirming the living nature of the polymerization,a plot of Mn (obtained by SEC-MALS) vs[M]0/[I]0 for the Arg8 monomer yields a linearfit for [M]0/[I]0 less than 9 (Figure 2A and Table 2). At larger[M]0/[I]0 ratios, propagation ceased, presumablydue to steric hindrance encountered from assembling multiple copiesof the long, side-chain protected peptide sequence, whose molecularweight as a monomer is 3.5 kDa. A similar plot was obtained from datagathered for polymerization of the Tat polymer, collected by staticlight scattering (SLS) in a cuvette (Figure 2B and Table 2). Therefore, we conclude thatboth CPP monomers are polymerized in a living fashion to a DP of <9,despite the complexity and functionality of their side chains, makingthis an exceptionally convenient strategy for predictably generatingpolymeric architectures from peptide monomers.

Bottom Line: We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers.The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells.The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry & Biochemistry, ‡Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego , La Jolla, California 92093, United States.

ABSTRACT
We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers. The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells. The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease. Finally, we demonstrate that the proteolytic susceptibility of peptide brush polymers can be tuned by adjusting the density of the polymer brush and offer in silico models to rationalize this finding. We contend that this strategy offers a plausible method of preparing peptides for in vivo use, where rapid digestion by proteases has traditionally restricted their utility.

Show MeSH
Related in: MedlinePlus