Related Experiment Video
Updated: May 18, 2026
06:55
Using Caenorhabditis elegans to Screen for Tissue-Specific Chaperone Interactions
Published on: June 7, 2020
Allosteric mechanism controls traffic in the chaperone/usher pathway
Xiao Di Yu1, Anatoly Dubnovitsky, Alex F Pudney
1Department of Molecular Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, BMC, Box 590, SE-75324 Uppsala, Sweden.
Structure (London, England : 1993)
|September 18, 2012
Summary
Gram-negative bacteria assemble virulence organelles using the chaperone/usher pathway. A "proline lock" in the chaperone controls usher binding, ensuring correct targeting and subunit release for F1 capsule assembly in Yersinia pestis.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Many Gram-negative bacterial pathogens utilize the chaperone/usher pathway for assembling virulence organelles.
- This pathway involves chaperones transporting subunits to outer membrane ushers for fiber incorporation.
Purpose of the Study:
- To elucidate the atomic-level mechanism of usher targeting during the assembly of the Yersinia pestis F1 capsule.
- To understand the role of the chaperone-subunit interaction in this process.
Main Methods:
- Atomic-level structural analysis.
- Biochemical assays to study protein interactions.
Main Results:
- The usher primarily interacts with the chaperone within the chaperone:subunit complex.
- A "proline lock" in the free chaperone blocks usher-binding sites.
- Subunit binding to the chaperone repositions the proline lock, enabling usher interaction.
Conclusions:
- The "proline lock" mechanism is crucial for selective targeting of chaperone:subunit complexes to the usher.
- This allosteric mechanism facilitates the release and recycling of free chaperones.
- The findings offer insights into a general mechanism applicable to other chaperone/usher systems.
Related Concept Videos
01:08Allosteric Regulation
Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
01:08Allosteric Regulation
Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...