Structure-Activity-Property Relationships of MZ1-Based Trivalent PROTACs Incorporating a 1,2,5-Trisubstituted Benzene
Yifan Huang1, Toshio Kaneda2, Mai Murata2
1Graduate School of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
Chemical & Pharmaceutical Bulletin
|July 30, 2026
Summary
Adding polar groups to MZ1 proteolysis-targeting chimeras (PROTACs) improves solubility but reduces Brd4 degradation activity. Capping these polar groups restores PROTAC efficacy, aiding future drug design.
Area of Science:
- Medicinal Chemistry
- Molecular Biology
- Drug Discovery
Background:
- Proteolysis-targeting chimeras (PROTACs) are an emerging therapeutic modality.
- MZ1-based PROTACs utilize a trisubstituted benzene linker for targeted protein degradation.
- Understanding structure-activity-property relationships is crucial for optimizing PROTAC design.
Purpose of the Study:
- To investigate the impact of linker modifications on MZ1-based PROTACs.
- To evaluate the effect of polar functional groups on PROTAC solubility and activity.
- To elucidate the role of linker substituents in Brd4 degradation.
Main Methods:
- Synthesis of MZ1-based PROTACs with varying 1,2,5-trisubstituted benzene linkers.
- Assessment of PROTAC solubility using biophysical methods.
- Evaluation of Brd4 degradation activity in cellular assays.
- Analysis of ternary complex formation.
Main Results:
- Introduction of a polar, charged functional group at the linker's terminus enhanced PROTAC solubility.
- This polar modification significantly diminished Brd4 degradation-inducing activity.
- Capping the polar functional group successfully restored the PROTAC's degradation efficacy.
- PROTACs were designed to maintain ternary complex formation, yet activity was impacted.
Conclusions:
- Linker functionalization in MZ1-based PROTACs presents a trade-off between solubility and degradation activity.
- Strategic capping of polar groups is essential for restoring PROTAC function.
- These findings inform the rational design of novel PROTACs and chemical probes.
- Further insights into PROTAC mechanism of action are provided.
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