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Updated: Jun 3, 2026
05:33
Using Modified Synthetic Oligonucleotides to Assay Nucleic Acid-Metabolizing Enzymes
Published on: July 5, 2024
Scope and limitation of side-chain assisted ligation
Liat Spasser1, K S Ajish Kumar, Ashraf Brik
1Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
Summary
Side-chain assisted ligation uses a thiol-bearing auxiliary on amino acid side chains to enable peptide bond formation, similar to native chemical ligation. The auxiliary is then easily removed under mild alkaline conditions.
Area of Science:
- Chemical Biology
- Organic Chemistry
- Biochemistry
Background:
- Native chemical ligation (NCL) is a powerful method for peptide synthesis.
- Cysteine residues are essential for NCL, limiting its application in proteins lacking cysteine.
- Alternative ligation strategies are needed to expand the scope of peptide synthesis.
Purpose of the Study:
- To develop a novel auxiliary-mediated ligation strategy.
- To enable ligation at non-cysteine residues.
- To provide a method for efficient peptide synthesis.
Main Methods:
- Attachment of a thiol-bearing auxiliary (cyclohexane or cyclopentane) to Asp, Glu, Ser, or Thr side chains.
- Performing ligation reactions mediated by the auxiliary.
- Removal of the auxiliary under alkaline conditions.
Main Results:
- Successful ligation at Asp, Glu, Ser, and Thr residues.
- Demonstration of auxiliary removal without product isolation.
- High efficiency of the ligation and deprotection steps.
Conclusions:
- Side-chain assisted ligation is a viable alternative to NCL for peptide synthesis.
- This method expands the possibilities for synthesizing peptides and proteins.
- The auxiliary can be efficiently removed under mild conditions, simplifying the process.
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