VH032 thiol

Target: This ligand targets von Hippel-Lindau protein (VHL), the substrate receptor of the CRL2VHL E3 ligase in biochemical or cellular target-engagement studies.

Mechanism of Action: VH032 thiol is used primarily as an E3 ligase recognition element rather than a protein-of-interest ligand. In PROTAC construction, it can be coupled through its functional handle to a linker and a separate target-binding ligand, generating a heterobifunctional molecule that recruits the CRL2VHL ubiquitin ligase complex. Productive ternary-complex formation places the selected target protein near the VHL-associated E3 machinery. When the linker and exit vectors support favorable geometry, the recruited ligase promotes target lysine ubiquitination, followed by proteasome-dependent degradation in experimental systems.

• Cysteine-Targeted PROTAC Design: VH032 thiol can be used as a reactive warhead within PROTAC constructs to engage cysteine-containing binding sites on the target protein. This enables covalent or semi-covalent recruitment to the target, potentially improving ternary complex stability and supporting efficient ubiquitination-driven degradation in cellular degradation assays.

• Ternary Complex Stabilization: Incorporating VH032 thiol into a PROTAC framework can help tune the kinetics and residence time of target engagement, which is critical for productive ternary complex formation with an E3 ligase. Researchers can evaluate degradation potency by varying linker length and attachment chemistry to optimize cooperative binding and ubiquitin transfer.

• Mechanism-Guided Degradation Studies: VH032 thiol-based PROTACs are suitable for dissecting degradation mechanisms, including dependence on cysteine reactivity and ubiquitin-proteasome pathway engagement. Experimental designs may include competition with thiol-reactive controls, proteasome inhibition, and time-resolved immunoblotting to distinguish binding, ubiquitination, and degradation steps.

• Structure–Reactivity Optimization: VH032 thiol can serve as a platform for systematic structure–reactivity studies in targeted protein degradation. By modifying electrophilicity, steric accessibility, and conjugation position, researchers can map how warhead chemistry influences target engagement, off-target labeling risk, and the resulting degradation selectivity across related protein isoforms.

VH032 thiol is a VHL-recruiting ligand designed for constructing VHL-based PROTACs through sulfur-selective linker chemistry. It is useful when a thiol-reactive handle is desired for modular degrader assembly.

Structure: VH032 thiol is a VHL ligand derivative containing the hydroxyproline-based VHL recognition motif and a sulfur-bearing side-chain handle. The structure includes multiple amide-type hydrogen-bonding elements, a stereochemically defined pyrrolidine core, and a thiazoline/thioamide-like sulfur-containing region.

Reactivity: VH032 thiol is best used as the E3 ligase ligand component for VHL-recruiting PROTAC construction rather than as a target-protein ligand. The thiol handle can be paired with maleimide, haloacetamide, activated disulfide, acrylamide, or other thiol-selective linkers to generate thioether or reversible disulfide conjugates. Alkyl or PEG linker systems can be selected to tune spacing, polarity, and ternary-complex geometry while preserving the VHL-recognition core.