Related Experiment Video
Updated: Feb 13, 2026
05:27
Immunization of Alpacas Lama pacos with Protein Antigens and Production of Antigen-specific Single Domain Antibodies
Published on: January 26, 2019
24.7K
Structural Basis for the Specific Neutralization of Stx2a with a Camelid Single Domain Antibody Fragment
Robert Alvin Bernedo-Navarro1, Ema Romão2, Tomomasa Yano3
1Laboratory of Bacterial Genetics, Institute of Biology, University of Campinas (UNICAMP), São Paulo 13083-862, Brazil. alvinbn@gmail.com.
Toxins
|March 2, 2018
Summary
Researchers developed nanobodies (Nbs) to neutralize Shiga toxin 2a (Stx2a). The best nanobody, Nb113, binds to Stx2a and blocks Gb3 receptor interaction, effectively neutralizing the toxin, especially in a bivalent format.
Area of Science:
- Biotechnology
- Immunology
- Structural Biology
Background:
- Shiga toxin-producing Escherichia coli (STEC) cause severe human illnesses.
- Shiga toxins (Stx) are key virulence factors, with Stx2 often linked to severe pathologies.
- Stx2a is a significant human pathogen, necessitating effective neutralization strategies.
Purpose of the Study:
- To develop and characterize novel nanobodies (Nbs) for neutralizing Shiga toxin 2a (Stx2a).
- To elucidate the structural basis of Stx2a neutralization by specific nanobodies.
- To evaluate the efficacy of monovalent and bivalent nanobody formats for toxin neutralization.
Main Methods:
- Construction of an immune nanobody library after alpaca immunization with recombinant Stx2a B subunit (rStx2aB).
- Specificity and affinity validation of nanobodies using ELISA and Western blot.
- X-ray crystallography to determine the complex structure of Nb113 with rStx2aB.
- Vero cell-based assays to assess Stx2a neutralization capacity.
Main Results:
- Five rStx2aB-specific nanobodies were identified, with Nb113 showing the highest affinity (9.6 nM).
- The crystal structure revealed Nb113 binding to the rStx2aB pentamer, overlapping the Gb3 receptor site.
- Bivalent Nb113₂ demonstrated a 100-fold higher functional affinity and superior Stx2a neutralization compared to monovalent Nb113.
- Nb113 neutralizes Stx2a by competitively inhibiting Gb3 receptor binding.
Conclusions:
- Nb113 is a potent Stx2a and Stx2c neutralizing nanobody, particularly effective in its bivalent form (Nb113₂).
- The mechanism of neutralization involves blocking the Gb3 binding site, preventing toxin interaction with host cells.
- Future strategies may involve fusing bivalent nanobodies with serum albumin binders to enhance circulation time and therapeutic potential.
More Related Videos
07:55Generation of Escape Variants of Neutralizing Influenza Virus Monoclonal Antibodies
Published on: August 29, 2017
12.3K
10:17Creating Highly Specific Chemically Induced Protein Dimerization Systems by Stepwise Phage Selection of a Combinatorial Single-Domain Antibody Library
Published on: January 14, 2020
8.3K
Related Concept Videos
01:10Antibody Structure
65.8K
Overview
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
65.8K
01:25Antibody Structure and Classes
9.4K
Antibodies, also known as immunoglobulins, are produced by B cells in response to foreign substances, such as bacteria and viruses. These proteins are critical for recognizing and neutralizing these substances, protecting the body from potential harm.
The basic structure of an antibody consists of four protein chains: two identical heavy chains and two identical light chains. These chains are held together by disulfide bonds and other non-covalent interactions, forming a Y-shaped structure.
The basic structure of an antibody consists of four protein chains: two identical heavy chains and two identical light chains. These chains are held together by disulfide bonds and other non-covalent interactions, forming a Y-shaped structure.
9.4K
02:26Conservation of Protein Domains Over Different Proteins
14.7K
Protein domains are small structurally independent units that are part of a single amino acid chain. Although these domains are often structurally independent, they may rely on synergistic effects to perform their functions as part of a larger protein. Protein domains may be conserved within the same organism, as well as across different organisms.
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
14.7K
02:31Habitat Fragmentation
21.5K
Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land conversion, as well as slower geological processes leading to changes in the physical environment, are the two leading causes of habitat fragmentation. The fragmentation process typically follows the same steps: perforation, dissection, fragmentation, shrinkage, and attrition.
21.5K
03:26Acids, Bases and Neutralization Reactions
64.0K
An acid-base reaction is one in which a hydrogen ion, H+, is transferred from one chemical species to another. Such reactions are of central importance to numerous natural and technological processes, ranging from the chemical transformations within cells or lakes and oceans to the industrial-scale production of fertilizers, pharmaceuticals, and other substances essential to the society.
64.0K
01:29Three Developmental Domains
1.2K
Human development is typically examined across three main domains: physical, cognitive, and socio-emotional. These domains represent the significant areas of change and continuity throughout the lifespan, from infancy to late adulthood.
Physical Development
Physical processes, also known as maturation, encompass the biological changes that occur across an individual's life. These changes begin with genetic inheritance and continue through various stages, including growth in height and weight,...
Physical Development
Physical processes, also known as maturation, encompass the biological changes that occur across an individual's life. These changes begin with genetic inheritance and continue through various stages, including growth in height and weight,...
1.2K