Braces for the Peptide Backbone: Insights into Structure–Activity Relationships of Protease Inhibitor Mimics with Locked Amide Conformations

Tischler, Marco; Nasu, Daichi; Empting, Martin; Schmelz, Stefan; Heinz, Dirk W.; Rottmann, Philipp; Kolmar, Harald; Buntkowsky, Gerd; Tietze, Daniel; Avrutina, Olga

doi:10.1002/anie.201108983

Cited by 69 publications

(62 citation statements)

References 50 publications

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“…42 Tischler et al . 43 proposed strategies for locking the amide bond leading to one particular conformation by incorporating triazole based mimetics in the peptide. Such strategies could be used in the future to lock SFTI-a into one conformation.…”

Section: Resultsmentioning

confidence: 99%

Constrained Cyclic Peptides as Immunomodulatory Inhibitors of the CD2:CD58 Protein–Protein Interaction

et al. 2016

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The interaction between the cell–cell adhesion proteins CD2 and CD58 plays a crucial role in lymphocyte recruitment to inflammatory sites, and inhibitors of this interaction have potential as immunomodulatory drugs in autoimmune diseases. Peptides from the CD2 adhesion domain were designed to inhibit CD2:CD58 interactions. To improve the stability of the peptides, β-sheet epitopes from the CD2 region implicated in CD58 recognition were grafted into the cyclic peptide frameworks of sunflower trypsin inhibitor and rhesus theta defensin. The designed multicyclic peptides were evaluated for their ability to modulate cell–cell interactions in three different cell adhesion assays, with one candidate, SFTI-a, showing potent activity in the nanomolar range (IC50: 51 nM). This peptide also suppresses the immune responses in T cells obtained from mice that exhibit the autoimmune disease rheumatoid arthritis. SFTI-a was resistant to thermal denaturation, as judged by circular dichroism spectroscopy and mass spectrometry, and had a half-life of ~24 h in human serum. Binding of this peptide to CD58 was predicted by molecular docking studies and experimentally confirmed by surface plasmon resonance experiments. Our results suggest that cyclic peptides from natural sources are promising scaffolds for modulating protein–protein interactions that are typically difficult to target with small-molecule compounds.

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Section: Resultsmentioning

confidence: 99%

Constrained Cyclic Peptides as Immunomodulatory Inhibitors of the CD2:CD58 Protein–Protein Interaction

et al. 2016

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“…The Michaelis-Menten constant K m for the substrates and proteases were determined previously [49], [64].…”

Section: Methodsmentioning

confidence: 99%

Combinatorial Optimization of Cystine-Knot Peptides towards High-Affinity Inhibitors of Human Matriptase-1

et al. 2013

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Cystine-knot miniproteins define a class of bioactive molecules with several thousand natural members. Their eponymous motif comprises a rigid structured core formed by six disulfide-connected cysteine residues, which accounts for its exceptional stability towards thermic or proteolytic degradation. Since they display a remarkable sequence tolerance within their disulfide-connected loops, these molecules are considered promising frameworks for peptide-based pharmaceuticals. Natural open-chain cystine-knot trypsin inhibitors of the MCoTI (Momordica cochinchinensis trypsin inhibitor) and SOTI (Spinacia oleracea trypsin inhibitor) families served as starting points for the generation of inhibitors of matriptase-1, a type II transmembrane serine protease with possible clinical relevance in cancer and arthritic therapy. Yeast surface-displayed libraries of miniproteins were used to select unique and potent matriptase-1 inhibitors. To this end, a knowledge-based library design was applied that makes use of detailed information on binding and folding behavior of cystine-knot peptides. Five inhibitor variants, four of the MCoTI family and one of the SOTI family, were identified, chemically synthesized and oxidatively folded towards the bioactive conformation. Enzyme assays revealed inhibition constants in the low nanomolar range for all candidates. One subnanomolar binder (Ki = 0.83 nM) with an inverted selectivity towards trypsin and matriptase-1 was identified.

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“…Additionally, these moieties can substitute disulfide bonds resulting in redox-stable constructs. Although these building blocks has not been yet applied to tridisulfide peptides, their viability was demonstrated using the scaffold of single-disulfide sunflower trypsin inhibitor I (SFTI-I) [126,127].…”

Section: Box 4: Triazolyl-bearing Peptidomimetics For Miniprotein Engmentioning

confidence: 99%

Synthetic Cystine-Knot Miniproteins – Valuable Scaffolds for Polypeptide Engineering

Avrutina

2016

Advances in Experimental Medicine and Biology

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Peptides with the cystine-knot architecture, often termed knottins, are promising scaffolds for biomolecular engineering. These unique molecules combine diverse bioactivities with excellent structural, thermal, and proteolytical stability. Being different in the composition and structure of their amino acid backbone, knottins share the same core element, namely cystine knot, which is built by six cysteine residues forming three disulfides upon oxidative folding. This motif ensures a notably rigid framework that highly tolerates both rational and combinatorial changes in the primary structure. Being accessible through recombinant production and total chemical synthesis, cystine-knot miniproteins can be endowed with novel bioactivities by variation of surface-exposed loops and incorporation of non-natural elements within their non-conserved regions towards the generation of tailor-made peptidic compounds. In this chapter the topology of cystine-knot peptides, their synthesis and applications for diagnostics and therapy is discussed.

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Braces for the Peptide Backbone: Insights into Structure–Activity Relationships of Protease Inhibitor Mimics with Locked Amide Conformations

Cited by 69 publications

References 50 publications

Constrained Cyclic Peptides as Immunomodulatory Inhibitors of the CD2:CD58 Protein–Protein Interaction

Constrained Cyclic Peptides as Immunomodulatory Inhibitors of the CD2:CD58 Protein–Protein Interaction

Combinatorial Optimization of Cystine-Knot Peptides towards High-Affinity Inhibitors of Human Matriptase-1

Synthetic Cystine-Knot Miniproteins – Valuable Scaffolds for Polypeptide Engineering

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