2fmx: Difference between revisions
No edit summary |
No edit summary |
||
| Line 4: | Line 4: | ||
|PDB= 2fmx |SIZE=350|CAPTION= <scene name='initialview01'>2fmx</scene>, resolution 1.82Å | |PDB= 2fmx |SIZE=350|CAPTION= <scene name='initialview01'>2fmx</scene>, resolution 1.82Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=GDP:GUANOSINE-5 | |LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=GDP:GUANOSINE-5'-DIPHOSPHATE'>GDP</scene> | ||
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| Line 35: | Line 35: | ||
[[Category: sar1]] | [[Category: sar1]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 23 15:06:31 2008'' | ||
Revision as of 13:06, 23 March 2008
| |||||||||||||
| 2fmx, resolution 1.82Å | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ligands: | SO4, MG and GDP | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
An open conformation of switch I revealed by Sar1-GDP crystal structure at low Mg(2+)
Overview
Mg2+ is essential for guanosine triphosphatase activity and plays key roles in guanine nucleotide binding and preserving the structural integrity of GTP-binding proteins. To understand the structural basis for Mg2+ function during the GDP/GTP exchange process, we determined the crystal structure of Delta9-Sar1-GDP at low Mg2+ concentration at 1.8A. Two Sar1-GDP molecules in the crystal form a dimer with Mg2+ presenting only in molecule B but not in molecule A. The absence of Mg2+ induces significant conformational changes in the switch I region in molecule A that shows similarities with those of Ha-Ras bound to Sos. The current structure reveals an important regulatory role for Mg2+. We suggest that guanine nucleotide exchange factor may utilize this feature to generate an open conformation for GDP/GTP exchange. Furthermore, we propose a mechanism for COPII assembly and disassembly in which dimerization of Sar1 plays an important role.
About this Structure
2FMX is a Single protein structure of sequence from Cricetulus griseus. Full crystallographic information is available from OCA.
Reference
An open conformation of switch I revealed by Sar1-GDP crystal structure at low Mg2+., Rao Y, Bian C, Yuan C, Li Y, Chen L, Ye X, Huang Z, Huang M, Biochem Biophys Res Commun. 2006 Sep 29;348(3):908-15. Epub 2006 Aug 1. PMID:16899220
Page seeded by OCA on Sun Mar 23 15:06:31 2008
