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Peptide ligands for a sugar-binding protein isolated from a random peptide library
K R Oldenburg1, D Loganathan, I J Goldstein
1Department of Bioorganic Chemistry, Affymax Research Institute, Palo Alto, CA 94304.
Summary
Researchers discovered peptide ligands that bind to concanavalin A (Con A), a carbohydrate-binding protein. These peptides show potential for developing new therapeutic agents by inhibiting Con A
Area of Science:
- Biochemistry
- Molecular Biology
- Biotechnology
Background:
- Concanavalin A (Con A) is a well-characterized lectin that binds specifically to mannose and glucose residues.
- Identifying high-affinity ligands for lectins is crucial for developing diagnostic and therapeutic tools.
- Traditional methods for identifying ligands can be complex and time-consuming.
Purpose of the Study:
- To identify novel peptide ligands that bind to Concanavalin A (Con A).
- To characterize the binding affinity and inhibitory potential of identified peptides.
- To explore the utility of peptide ligands as alternatives to carbohydrate ligands for Con A.
Main Methods:
- Screening of a large, diverse peptide library displayed on filamentous phage.
- Affinity determination using dissociation constant (Kd) measurements.
- Inhibition assays to assess the competitive binding of peptides against known ligands.
Main Results:
- A dodecapeptide with the consensus sequence Tyr-Pro-Tyr was identified.
- This peptide exhibited a dissociation constant (Kd) of 46 microM for Con A.
- The peptide's binding affinity was comparable to methyl alpha-D-mannopyranoside (Kd = 89 microM).
- The identified peptide inhibited the precipitation of dextran by Con A.
Conclusions:
- Peptide ligands can effectively bind to carbohydrate-binding proteins like Con A.
- The Tyr-Pro-Tyr peptide represents a promising lead for Con A-specific inhibitor development.
- Peptide-based inhibitors offer a potentially simpler alternative to complex oligosaccharide synthesis for therapeutic applications.