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Azide-alkyne cycloaddition-mediated cyclization of phosphonopeptides and their evaluation as PTP1B binders and
Christoph Meyer1, Birgit Hoeger1, Jayanta Chatterjee1
1European Molecular Biology Laboratory, Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Abstract:
Protein tyrosine phosphatases (PTPs) are important enzymes in health and disease, and chemical tools are crucial to understand and modulate their biological roles. PTP1B is involved in diabetes, obesity and cancer. One of the main challenges for the design of chemical tools for PTP1B is the homology to TCPTP, making tool selectivity a highly challenging task. Here, we aimed to study if azide-alkyne cycloaddition-mediated cyclization of a peptide inhibitor could increase its selectivity toward PTP1B over TCPTP, and if cyclic and linear peptide binders can be applied as enrichment tools of endogenous PTP1B. While the cyclization of the peptide binders did not improve the selectivity toward PTP1B over TCPTP, it enhanced strongly the efficiency to co-precipitate endogenous PTP1B out of cell lysates. Our results show that fine-tuning the molecular structure of peptidic pull-down baits can greatly enhance their efficiency compared to the parental peptide sequences.
Insights
Cyclizing peptide inhibitors enhanced their ability to isolate protein tyrosine phosphatase 1B (PTP1B) from cell samples, though selectivity over similar enzymes remained a challenge. Molecular structure tuning improves pull-down bait efficiency.
Area of Science:
- Biochemistry
- Chemical Biology
- Enzymology
Background:
- Protein tyrosine phosphatases (PTPs) are critical enzymes in cellular signaling, implicated in diseases like diabetes, obesity, and cancer.
- Developing selective chemical tools for PTPs, particularly PTP1B, is challenging due to high homology with other PTPs like TCPTP.
Purpose of the Study:
- To investigate if azide-alkyne cycloaddition-mediated cyclization of a peptide inhibitor enhances selectivity for PTP1B over TCPTP.
- To assess the utility of cyclic and linear peptide binders for enriching endogenous PTP1B from cell lysates.
Main Methods:
- Synthesis of cyclic and linear peptide inhibitors targeting PTP1B.
- Evaluation of enzyme selectivity using biochemical assays.
- Application of peptide binders for co-precipitation of endogenous PTP1B from cell lysates.
Main Results:
- Peptide cyclization did not improve selectivity of the inhibitor for PTP1B against TCPTP.
- Cyclization significantly enhanced the efficiency of peptide binders in co-precipitating endogenous PTP1B.
- Fine-tuning the molecular structure of peptidic pull-down baits boosted their efficiency compared to linear sequences.
Conclusions:
- While cyclization did not confer selectivity, it markedly improved the efficacy of peptide binders for PTP1B enrichment.
- Structural modifications of peptidic probes are key to enhancing their performance as pull-down tools for specific protein targets.
