The Structure of the Yeast Plasma Membrane SNARE Complex Reveals Destabilizing Water-filled Cavities*
- Howard Hughes Medical Institute and Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences, Structural Biology, and Photon Science, Stanford University, Stanford, California 94305
- ↵1 To whom correspondence should be addressed. Tel.: 650-736-1809; Fax: 650-736-1961; E-mail: brunger{at}stanford.edu.
Abstract
SNARE proteins form a complex that leads to membrane fusion between vesicles, organelles, and plasma membrane in all eukaryotic cells. We report the 1.7Å resolution structure of the SNARE complex that mediates exocytosis at the plasma membrane in the yeast Saccharomyces cerevisiae. Similar to its neuronal and endosomal homologues, the S. cerevisiae SNARE complex forms a parallel four-helix bundle in the center of which is an ionic layer. The S. cerevisiae SNARE complex exhibits increased helix bending near the ionic layer, contains water-filled cavities in the complex core, and exhibits reduced thermal stability relative to mammalian SNARE complexes. Mutagenesis experiments suggest that the water-filled cavities contribute to the lower stability of the S. cerevisiae complex.
- Received September 21, 2007.
- Revision received October 22, 2007.
- The American Society for Biochemistry and Molecular Biology, Inc.
