• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Structure of the Sec23/24-Sar1 pre-budding complex of the COPII vesicle coat.

COPII-coated vesicles form on the endoplasmic reticulum by the stepwise recruitment of three cytosolic components: Sar1-GTP to initiate coat formation, Sec23/24 heterodimer to select SNARE and cargo molecules, and Sec13/31 to induce coat polymerization and membrane deformation. Crystallographic analysis of the Saccharomyces cerevisiae Sec23/24-Sar1 complex reveals a bow-tie-shaped structure, 15 nm long, with a membrane-proximal surface that is concave and positively charged to conform to the size and acidic-phospholipid composition of the COPII vesicle. Sec23 and Sar1 form a continuous surface stabilized by a non-hydrolysable GTP analogue, and Sar1 has rearranged from the GDP conformation to expose amino-terminal residues that will probably embed in the bilayer. The GTPase-activating protein (GAP) activity of Sec23 involves an arginine side chain inserted into the Sar1 active site. These observations establish the structural basis for GTP-dependent recruitment of a vesicular coat complex, and for uncoating through coat-controlled GTP hydrolysis.

Pubmed ID: 12239560

Authors

  • Bi X
  • Corpina RA
  • Goldberg J

Journal

Nature

Publication Data

September 19, 2002

Associated Grants

None

Mesh Terms

  • Amino Acid Sequence
  • Binding Sites
  • Biological Transport
  • COP-Coated Vesicles
  • Crystallography, X-Ray
  • Dimerization
  • GTPase-Activating Proteins
  • Guanosine Diphosphate
  • Guanosine Triphosphate
  • Hydrolysis
  • Macromolecular Substances
  • Membrane Proteins
  • Models, Molecular
  • Molecular Sequence Data
  • Monomeric GTP-Binding Proteins
  • Protein Binding
  • Protein Isoforms
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Vesicular Transport Proteins