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Interactions within the yeast t-SNARE Sso1p that control SNARE complex assembly
1Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
Nature Structural Biology
|October 4, 2000
Summary
Researchers visualized the closed conformation of yeast syntaxin (Sso1p) using X-ray crystallography. Mutants destabilizing this conformation accelerated SNARE complex assembly, revealing insights into intracellular trafficking regulation.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Intracellular trafficking relies on transport vesicles fusing with target membranes.
- SNARE protein complexes mediate vesicle fusion.
- Syntaxin proteins, including yeast Sso1p, adopt a closed conformation that inhibits SNARE assembly.
Purpose of the Study:
- To visualize the closed conformation of yeast syntaxin (Sso1p) directly.
- To investigate how this conformation regulates SNARE complex assembly.
- To understand the mechanisms controlling intracellular trafficking.
Main Methods:
- X-ray crystallography was used to determine the structure of yeast Sso1p.
- Site-directed mutagenesis was employed to create mutants destabilizing the closed conformation.
- In vitro assays measured the rates of SNARE assembly.
Main Results:
- The X-ray crystal structure of yeast Sso1p in its closed conformation was determined to 2.1 A resolution.
- Mutants designed to destabilize the closed conformation showed faster SNARE assembly rates.
- These findings provide direct visualization of the inhibitory conformation.
Conclusions:
- The closed conformation of syntaxins plays a critical role in regulating SNARE assembly.
- Destabilizing this conformation enhances SNARE complex formation.
- This study offers insights into the intramolecular and intermolecular regulation of intracellular transport.
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