2-(2'-pyridyldithio)benzyldiazoacetate

Description

2-(2'-pyridyldithio)benzyldiazoacetate (also known as **PySSPhCH2CHN2**) is a **photoactivatable crosslinking reagent** used in **biochemical research**.

Here's a breakdown of its importance:

**Structure and Properties:**

* **Diazoacetate moiety:** This group makes the molecule highly reactive towards light. Upon UV irradiation, it releases nitrogen gas and generates a reactive **carbene** intermediate.
* **2'-Pyridyldithio group:** This acts as a **cleavable linker**. It can be readily attached to proteins or other biomolecules through disulfide bond formation. The disulfide bond is relatively stable under normal conditions but can be cleaved under reducing conditions, allowing for separation of the tagged molecule.
* **Benzyl group:** Provides a spacer between the reactive diazoacetate group and the disulfide linker, allowing for greater flexibility and optimal positioning during crosslinking.

**How it works:**

1. **Attachment:** PySSPhCH2CHN2 is covalently attached to a target molecule (e.g., a protein) via its disulfide bond.
2. **UV irradiation:** When the modified molecule is exposed to UV light, the diazoacetate group generates a carbene.
3. **Crosslinking:** The carbene reacts with nearby molecules, forming a **covalent bond** between the tagged molecule and its target.
4. **Cleavage:** The disulfide bond can be cleaved under reducing conditions (e.g., using DTT or β-mercaptoethanol) to release the crosslinked target molecule.

**Importance in Research:**

* **Investigating protein-protein interactions:** PySSPhCH2CHN2 can be used to identify and study interactions between proteins within cells or in vitro. By crosslinking interacting proteins, they can be isolated and analyzed.
* **Mapping protein-DNA interactions:** This reagent can help to determine the specific regions of proteins that bind to DNA, providing insights into gene regulation and other cellular processes.
* **Developing new therapeutic agents:** Understanding the interactions between molecules can be crucial for designing new drugs or therapies.

**Advantages:**

* **Photoactivatable:** Crosslinking only occurs upon UV irradiation, providing high spatial and temporal control.
* **Cleavable linker:** Allows for easy separation and identification of crosslinked products.
* **Versatile:** Applicable to a wide range of biomolecules and biological systems.

**Limitations:**

* **UV sensitivity:** May cause damage to certain molecules or cellular components.
* **Limited to surface accessible regions:** Only molecules that are within reach of the carbene intermediate can be crosslinked.
* **Potential for off-target crosslinking:** May react with unintended molecules, requiring careful analysis and interpretation.

**Overall, 2-(2'-pyridyldithio)benzyldiazoacetate is a valuable tool for researchers investigating molecular interactions and developing new therapeutic strategies.**

2-(2'-pyridyldithio)benzyldiazoacetate: structure given in first source; isomeric probe [Medical Subject Headings (MeSH), National Library of Medicine, extracted Dec-2023]