Amide I band and photoinduced disassembly of a peptide hydrogel

Measey, Thomas J.; Markiewicz, Beatrice N.; Gai, Feng

doi:10.1016/j.cplett.2013.06.055

Cited by 11 publications

(13 citation statements)

References 49 publications

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“… 42 , 43 The latter is a lysine analogue [hereafter termed Lys(nvoc)] with a photolabile hydrophobic moiety and has been used to control the disassembly of peptide aggregates and hydrogels via illumination. 44 , 45 Should Lys8 indeed serve as an aggregation gatekeeper of Trpzip2, we expect that this Trpzip2 mutant (hereafter termed Trpzip2-K) will exhibit a significantly stronger aggregation propensity.…”

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confidence: 99%

Aggregation Gatekeeper and Controlled Assembly of Trpzip β-Hairpins

Markiewicz

Oyola

et al. 2014

Biochemistry

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Protein and peptide aggregation is an important issue both in vivo and in vitro. Herein, we examine the aggregation behaviors of two well studied β-hairpins, Trpzip1 and Trpzip2. Previous studies suggest that Trpzip2 remains monomeric up to a concentration of ~15 mM whereas Trpzip1 readily aggregates at micromolar concentrations at acidic or neutral pH. This disparity is puzzling considering that these two peptides only differ in their turn sequences (i.e., GN versus NG). We hypothesize that these peptides can aggregate from their folded states via native edge-to-edge interactions and that the Lys8 residue in Trpzip2 is a more effective aggregation gatekeeper, due to a more favorable orientation. In support of this hypothesis, we find that raising the pH to 13 or replacing Lys8 with a hydrophobic and photolabile Lys analog, Lys(nvoc), leads to a significant increase in the aggregation propensity of Trpzip2, and that the aggregation of this Trpzip2 mutant can be reversed upon restoring the native Lys sidechain via photocleavage of the nvoc moiety. In addition, we find that while both Trpzip1 and Trpzip2 form parallel β-sheet aggregates, the Lys(nvoc) Trpzip2 mutant forms antiparallel β-sheets and more stable fibrils. Taken together, these findings provide another example showing how sensitive peptide and protein aggregation is to minor sequence variation and that it is possible to use a photolabile non-natural amino acid, such as Lys(nvoc), to tune the rate of peptide aggregation and to control fibrillar structure.

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confidence: 99%

Aggregation Gatekeeper and Controlled Assembly of Trpzip β-Hairpins

Markiewicz

Oyola

et al. 2014

Biochemistry

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“…To demonstrate photoactivity in the opposite direction, we recently showed that modification of two Phe residues in the peptide hydrogel sequence (FKFE) 2 with Lys(nvoc) preserves the ability of the peptide to form a macroscopic hydrogel as shown in the AFM image in Figure 7A. However, these mutations render the formed hydrogel photodegradable in response to light, as indicated in Figure 7B [121]. In a slightly different treatment, Griffin et al [122] utilized an ortho -nitrobenzyl cage as a photodegradable linker to tether a cell-adhesive peptide to a macromer-based hydrogel, thus allowing light-induced release.…”

Section: Manipulating Biological Assemblies With Lightmentioning

confidence: 99%

Tightening up the structure, lighting up the pathway: application of molecular constraints and light to manipulate protein folding, self-assembly and function

2014

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Chemical cross-linking provides an effective avenue to reduce the conformational entropy of polypeptide chains and hence has become a popular method to induce or force structural formation in peptides and proteins. Recently, other types of molecular constraints, especially photoresponsive linkers and functional groups, have also found increased use in a wide variety of applications. Herein, we provide a concise review of using various forms of molecular strategies to constrain proteins, thereby stabilizing their native states, gaining insight into their folding mechanisms, and/or providing a handle to trigger a conformational process of interest with light. The applications discussed here cover a wide range of topics, ranging from delineating the details of the protein folding energy landscape to controlling protein assembly and function.

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“…Hydrogels that respond to an exogenous stimulus to temporally modulate hydrogel rigidity and gel-sol/sol-gel transitions are desirable in the development of hydrogels for biomedical applications. 2,8,9 Environmental pH, 10 redox potential, 11 temperature, 12 ionic strength, 13 enzyme activation, 14,15 and light 16,17 have been exploited to promote self-assembly and hydrogel formation. Specically, designed amphipathic peptides containing b-hairpins have been employed to form well-ordered hydrogels that can be reversibly manipulated using pH, 18 temperature, 12,19 and ion complexation.…”

Section: Introductionmentioning

confidence: 99%