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High resolution structure, stability, and synaptotagmin binding of a truncated neuronal SNARE complex
James A Ernst1, Axel T Brunger
1Howard Hughes Medical Institute, Stanford University, California 94305, USA.
The Journal of Biological Chemistry
|December 24, 2002
Summary
A new high-resolution structure of the truncated SNARE complex reveals key stabilizing features and conformational details. This monomeric complex retains binding to synaptotagmin I, offering insights into membrane fusion mechanisms.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Neuroscience
Background:
- Soluble NSF Attachment Protein REceptor (SNARE) complexes mediate membrane fusion, a critical process in cellular function.
- Previous structural studies of SNARE complexes were limited by lower resolution, obscuring fine structural details.
Purpose of the Study:
- To determine the high-resolution structure of a truncated SNARE complex.
- To characterize the biophysical properties and binding interactions of the truncated SNARE complex.
Main Methods:
- X-ray crystallography to solve the structure to 1.4-Å resolution.
- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism (CD) thermal melts to assess thermal stability.
- Synaptotagmin I binding assays.
Main Results:
- A high-resolution structure revealed a stabilizing salt bridge, hydration sites, and conformational variability in the ionic layer.
- The truncated complex, lacking phospholipid-binding residues, denatures at lower temperatures.
- The truncated SNARE complex remains monomeric and binds synaptotagmin I.
Conclusions:
- High-resolution structural data provide unprecedented detail on SNARE complex organization.
- The truncated SNARE complex serves as a valuable model for studying the core structural and functional aspects of membrane fusion.
- Understanding SNARE complex structure and function is crucial for deciphering synaptic transmission and other cellular processes.