Caged Mono- and Divalent Ligands for Light-Assisted Disruption of PDZ Domain-Mediated Interactions

Abstract

We report a general method for light-assisted control of interactions of PDZ domain binding motifs with their cognate domains by the incorporation of a photolabile caging group onto the essential C-terminal carboxylate binding determinant of the motif. The strategy was implemented and validated for both simple monovalent and biomimetic divalent ligands, which have recently been established as powerful tools for acute perturbation of native PDZ domain-dependent interactions in live cells.

Small-molecule control of protein function through Staudinger reduction

“…The Staudinger reduction-induced deprotection of amino acids adds an additional tool to the expanding set of chemical and photochemical peptide and protein activation approaches. 21–26 Related reactions have been extensively used in bioconjugations in vitro and in vivo , and several types of Staudinger ligations have been reported. 27–29 Azide groups installed on biological molecules are non-toxic and fully orthogonal to all cellular chemistries as demonstrated by numerous examples of bioconjugation reactions in cells and whole organisms.…”

Mixing Biomimetic Heterodimers of Nucleopeptides to Generate Biocompatible and Biostable Supramolecular Hydrogels

“…We choose nucleobase (thymine or adenine) to connect with short peptide sequences (Scheme 1) from the binding interface of two well-characterized proteins, [18] calcium channel protein (stargazin [19] ) and synapse associated protein 102 (SAP102 [20] ). While the homonucleopeptides themselves are unable to self-assemble to form molecular nanofibers that result in a hydrogel, the mix of heteronucleopeptides, 1 + 3 and 2 + 3 , results in self-assembly to form supramolecular nanofiber/hydrogels.…”

“…Thef ormation of heterodimers implies rather strong noncovalent interactions at the interface of two proteins,t hus one should be able to take those complementary sequence to generate hydrogels.T his approach, in fact, has been explored by afew groups by using peptides to bind with proteins. [15] Fore xample,t he specific TPR-peptide, [15a] TIP1-peptide, [15b] and heparin-VEGF interaction, [15c] allows the formation of polymeric hydrogels.O ne drawback of this approach is the use of proteins being high-priced and susceptible to proteolysis.I nterestingly,t his approach has yet to be explored for the use of nucleopeptides [16] for creating supramolecular hydrogels.B ased on this principle,o ur work on supramolecular hydrogels made of homonucleopeptides by pH changes or enzymatic reactions, [16a] and the biostability of nucleopeptides, [16a, 17] we decided to explore the use of heteronucleopeptides to generate hydrogels by simple mixing of two structurally distinct nucleopeptides that bind with each other.We choose anucleobase (thymine or adenine) to connect with short peptide sequences (Scheme 1) from the binding interface of two well-characterized proteins, [18] calcium channel protein (stargazin [19] )a nd synapse-associated protein 102 (SAP102 [20] ). While the homonucleopeptides themselves are unable to self-assemble to form molecular nanofibers that result in ah ydrogel, the mix of heteronucleopeptides, 1 + 3 and 2 + 3,r esults in self-assembly to form supramolecular Scheme 1.…”

“…We choose anucleobase (thymine or adenine) to connect with short peptide sequences (Scheme 1) from the binding interface of two well-characterized proteins, [18] calcium channel protein (stargazin [19] )a nd synapse-associated protein 102 (SAP102 [20] ). While the homonucleopeptides themselves are unable to self-assemble to form molecular nanofibers that result in ah ydrogel, the mix of heteronucleopeptides, 1 + 3 and 2 + 3,r esults in self-assembly to form supramolecular nanofibers/hydrogels.F urthermore,t he nucleopeptides show excellent cell compatibilities,a nd the hydrogels of the heterodimers exhibit enhanced biostability.A st he first report of supramolecular hydrogels formed by mixing heterodimeric nucleopeptides,t his work illustrates af acile and rational methodology for creating nucleopeptides that act as an ew class of supramolecular hydrogelators for developing sophisticated soft materials according to the need of various applications.…”

Tailoring Chimeric Ligands for Studying and Biasing ErbB Receptor Family Interactions

“…Although examples of semisynthetic bivalent ligand constructs in the size range defined in this study are limited, other approaches for synthesizing bivalent assemblies have included application of solid-phase peptide synthesis (smaller peptidic ligands), [20a] site-selective incorporation of cysteines/ aldehydes into antibodies/proteins for subsequent ligation and linking by copper-catalyzed azide-alkyne click chemistry or metal-free click reactions, [21,22] as well as copper-catalyzed azide-alkyne cycloaddition chemistries on peptides [23] or on proteins containing incorporated unnatural amino acids. [24] We chose to employ sortase-mediated ligation because of robust conversion and small amino acid recognition sequences, thus allowing efficient near-native protein expression and ultimately increasing the final semisynthetic bivalent ligand yields (3-6 mg L À1 vs. multi-microgram/10 L for the coiledcoil and single-chain constructs).…”