Related Experiment Video

Updated: Jul 1, 2026

Modifying Baculovirus Expression Vectors to Produce Secreted Plant Proteins in Insect Cells
09:14

Modifying Baculovirus Expression Vectors to Produce Secreted Plant Proteins in Insect Cells

Published on: August 20, 2018

Location of the Bombyx mori 175kDa cadherin-like protein-binding site on Bacillus thuringiensis Cry1Aa toxin

Shogo Atsumi1, Yukino Inoue, Takahisa Ishizaka

  • 1Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Japan.

The FEBS Journal
|September 12, 2008
PubMed

Insights

Researchers identified the binding site of Bacillus thuringiensis Cry1Aa toxin on the Bombyx mori cadherin-like protein (BtR175). Tyr445 substitution disrupted binding, confirming its role in toxin-receptor interaction and insecticidal activity.

Area of Science:

  • * Molecular biology
  • * Insect toxicology
  • * Protein-ligand interactions

Background:

  • * Bacillus thuringiensis (Bt) Cry toxins are insecticidal proteins used in agriculture.
  • * Understanding the interaction between Cry toxins and insect receptors is crucial for developing effective pest control strategies.
  • * The cadherin-like protein from Bombyx mori (BtR175) is a known receptor for Cry toxins, but its precise binding site on the toxin remained unclear.

Purpose of the Study:

  • * To pinpoint the specific binding site of the cadherin-like receptor (BtR175) on the Bacillus thuringiensis Cry1Aa toxin.
  • * To investigate the functional significance of this binding site in the insecticidal activity of Cry1Aa toxin.

Main Methods:

  • * Utilized Cry1Aa toxin with a known 3D structure for binding site analysis.
  • * Employed monoclonal antibodies (mAbs) to block and identify the BtR175 binding site on Cry1Aa toxin.
  • * Constructed Cry1Aa toxin mutants by introducing cysteine substitutions and used N-(9-acridinyl)maleimide to probe the binding region.

Main Results:

  • * Two mAbs (2A11 and 2F9) were identified that inhibit BtR175 binding to Cry1Aa toxin.
  • * Analysis indicated the binding site is located in loops 2 and 3 of Cry1Aa toxin.
  • * Substitution of Tyr445 with cysteine in Cry1Aa toxin significantly impaired binding to BtR175, identifying Tyr445 as critical for interaction.

Conclusions:

  • * The Tyr445 residue on Cry1Aa toxin is located in or near the binding site for the Bombyx mori cadherin-like protein (BtR175).
  • * Binding of Cry1Aa toxin to BtR175 is essential for the toxin's insecticidal activity against Bombyx mori.
  • * This research provides a detailed understanding of the molecular basis for Cry1Aa toxin's interaction with its insect receptor.

More Related Videos

The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis13:00

The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis

Published on: December 11, 2012

Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG12:23

Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG

Published on: May 16, 2017

Related Concept Videos

Production of Biopesticides01:18

Production of Biopesticides

Biopesticides offer a sustainable alternative to chemical pesticides, utilizing microbial agents to control agricultural pests. Bacillus thuringiensis (Bt) is a widely employed bacterium known for its potent insecticidal activity. Bt biopesticides are favored for their specificity to insect pests, minimal environmental impact, and natural degradability.Mechanism of Bt Toxin Action Bt produces insecticidal crystal (Cry) proteins during its sporulation phase. These proteins form parasporal...
Globular and Fibrous Proteins02:21

Globular and Fibrous Proteins

Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Bacterial Toxins01:12

Bacterial Toxins

Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
Structure of Cadherins01:25

Structure of Cadherins

The cadherins were one of the first cell adhesion molecules discovered; the term “cadherins”   is based on their calcium-dependent adhering properties. The first cadherins discovered on the epithelial, neuronal, and placental cells were named E-cadherin, P-cadherin, and N-cadherin, respectively. These classical cadherins share sequence and structural similarities. Other cadherins, including those involved in cell signaling, are grouped into non-classical cadherins. This diversity of cadherins...
Receptor-mediated Endocytosis01:20

Receptor-mediated Endocytosis

Receptor-mediated endocytosis is when bulk amounts of specific molecules are imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle.
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...
Botulism01:22

Botulism

Botulism is a life-threatening neuroparalytic condition caused by botulinum neurotoxin, which is produced by the bacterium Clostridium botulinum, a Gram-positive, spore-forming, obligate anaerobe.In adults, the toxin enters the body in different ways: in foodborne botulism, the preformed toxin is absorbed in the intestine. In wound botulism, spores grow in injured tissue and release the toxin into the blood. Infant botulism differs mechanistically from adult forms. In infants, botulism commonly...