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Updated: Oct 2, 2025
08:58
Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques
Published on: July 5, 2018
12.8K
Structure and Carbohydrate Recognition by the Nonmitogenic Lectin Horcolin
Vaishali Narayanan1, Kishore Babu Bobbili1, Nukathoti Sivaji1
1Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
Biochemistry
|February 28, 2022
Summary
Horcolin, a nonmitogenic lectin, binds HIV-1 gp120 and neutralizes the virus. Structural analysis reveals two distinct carbohydrate-binding sites, suggesting allosteric communication crucial for antiviral activity against HIV-1.
Area of Science:
- Structural biology
- Biochemistry
- Virology
Background:
- Lectins show antiviral promise by targeting viral glycoproteins like HIV-1's gp120.
- Mitogenicity of some lectins limits their therapeutic use.
- Horcolin, a jacalin lectin, binds gp120 and neutralizes HIV-1 without being mitogenic.
Purpose of the Study:
- To elucidate the atomic-resolution structure of horcolin.
- To understand the molecular basis of horcolin's carbohydrate recognition.
- To investigate the structural basis for horcolin's nonmitogenic and antiviral properties.
Main Methods:
- X-ray crystallography for high-resolution structural determination.
- NMR spectroscopy for studying molecular interactions and binding dynamics.
- Site-directed mutagenesis to create single-binding-site variants.
Main Results:
- Horcolin dimer possesses a beta-prism I fold with two distinct carbohydrate-binding sites.
- Carbohydrate binding is stabilized by hydrogen bonds to conserved residues.
- NMR revealed a two-site binding mode with differing affinities and suggested allosteric communication between sites.
Conclusions:
- Horcolin's structure provides atomic insights into its nonmitogenic antiviral mechanism.
- The identified carbohydrate-binding sites and their allosteric communication are key to horcolin's interaction with viral glycans.
- Horcolin represents a promising lectin-based therapeutic candidate for HIV-1 treatment.
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