1m2o
From Proteopedia
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Crystal Structure of the Sec23-Sar1 complex
Overview
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.
About this Structure
1M2O is a Protein complex structure of sequences from Saccharomyces cerevisiae with ZN, MG and GNP as ligands. Full crystallographic information is available from OCA.
Reference
Structure of the Sec23/24-Sar1 pre-budding complex of the COPII vesicle coat., Bi X, Corpina RA, Goldberg J, Nature. 2002 Sep 19;419(6904):271-7. PMID:12239560
Page seeded by OCA on Tue Nov 20 21:05:47 2007
Categories: Protein complex | Saccharomyces cerevisiae | Bi, X. | Corpina, R.A. | Goldberg, J. | GNP | MG | ZN | Beta barrel | Gelsolin domain | Vwa domain | Zinc-finger
