(1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate

Description

(1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate, also known as **MTSL**, is a **spin label** commonly used in **Electron Paramagnetic Resonance (EPR) spectroscopy**.

Here's a breakdown of why MTSL is important in research:

**What is a spin label?**

* A spin label is a molecule with an unpaired electron, typically a **nitroxide radical**, that can be attached to a biomolecule (like a protein or lipid) to study its structure and dynamics.
* The unpaired electron in the spin label generates a detectable signal in EPR spectroscopy. This signal can provide information about the local environment of the spin label, such as its mobility, distance to other spin labels, and interactions with other molecules.

**Why MTSL is important:**

* **Versatility:** MTSL can be attached to a variety of biomolecules, making it a versatile tool for studying a wide range of systems.
* **Stability:** The nitroxide radical in MTSL is relatively stable, allowing for long-term experiments and measurements.
* **Reactivity:** MTSL contains a reactive **methanethiosulfonate group** that can be used to attach the spin label to specific amino acid residues in proteins, especially **cysteine residues**. This selective labeling allows researchers to target specific regions of the protein of interest.
* **Accessibility:** MTSL is readily available commercially, making it easy to obtain for research purposes.

**Research applications of MTSL:**

MTSL is used in a wide range of research applications, including:

* **Protein structure and dynamics:** Studying the folding, unfolding, and flexibility of proteins.
* **Protein-protein interactions:** Investigating how proteins interact with each other.
* **Membrane dynamics:** Examining the movement and interactions of lipids and proteins in cell membranes.
* **Enzyme mechanisms:** Studying the mechanism of action of enzymes and how their activity is affected by changes in their environment.
* **Drug discovery:** Identifying potential drug targets and understanding how drugs interact with their targets.

**In summary:**

(1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate (MTSL) is a valuable tool in research due to its versatility, stability, and reactivity. It enables scientists to gain insights into the structure, dynamics, and interactions of biomolecules through EPR spectroscopy. This information is crucial for understanding fundamental biological processes and developing new drugs and therapies.

(1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate: thiol-specific spin label; structure given in first source [Medical Subject Headings (MeSH), National Library of Medicine, extracted Dec-2023]

(1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate : An aminooxyl that is pyrroline substituted by an oxidanediyl group at position 1, by methyl groups at positions 2, 2, 5 and 5, and by a [(methylsulfonyl)sulfanyl]methyl group at position 3. It is a highly reactive thiol-specific spin label. [Chemical Entities of Biological Interest (ChEBI), Hastings J, Owen G, Dekker A, Ennis M, Kale N, Muthukrishnan V, Turner S, Swainston N, Mendes P, Steinbeck C. (2016). ChEBI in 2016: Improved services and an expanding collection of metabolites. Nucleic Acids Res]