1G17
CRYSTAL STRUCTURE OF SEC4-GUANOSINE-5'-(BETA,GAMMA)-IMIDOTRIPHOSPHATE
Summary for 1G17
| Entry DOI | 10.2210/pdb1g17/pdb |
| Related | 1G16 |
| Descriptor | RAS-RELATED PROTEIN SEC4, MAGNESIUM ION, PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER, ... (4 entities in total) |
| Functional Keywords | g protein rab, signaling protein, endocytosis-exocytosis complex, endocytosis/exocytosis |
| Biological source | Saccharomyces cerevisiae (baker's yeast) |
| Cellular location | Cytoplasmic vesicle, secretory vesicle membrane; Lipid-anchor; Cytoplasmic side: P07560 |
| Total number of polymer chains | 2 |
| Total formula weight | 39422.74 |
| Authors | Stroupe, C.,Brunger, A.T. (deposition date: 2000-10-10, release date: 2000-12-11, Last modification date: 2024-02-07) |
| Primary citation | Stroupe, C.,Brunger, A.T. Crystal structures of a Rab protein in its inactive and active conformations. J.Mol.Biol., 304:585-598, 2000 Cited by PubMed Abstract: We have determined crystal structures of Sec4, a member of the Rab family in the G protein superfamily, in two states: bound to GDP, and to a non-hydrolyzable GTP analog, guanosine-5'-(beta, gamma)-imidotriphosphate (GppNHp). This represents the first structure of a Rab protein bound to GDP. Sec4 in both states grossly resembles other G proteins bound to GDP and GppNHp. In Sec4-GppNHp, structural features common to active Rab proteins are observed. In Sec4-GDP, the switch I region is highly disordered and displaced relative to the switch I region of Ras-GDP. In two of the four molecules of Sec4-GDP in the asymmetric unit of the Sec4-GDP crystals, the switch II region adopts a conformation similar to that seen in the structure of the small G protein Ran bound to GDP. This allows residues threonine 76, glutamate 80, and arginine 81 of Sec4 to make contacts with other conserved residues and water molecules important for nucleotide binding. In the other two molecules in the asymmetric unit, these interactions do not take place. This structural variability in both the switch I and switch II regions of GDP-bound Sec4 provides a possible explanation for the high off-rate of GDP bound to Sec4, and suggests a mechanism for regulation of the GTPase cycle of Rab proteins by GDI proteins. PubMed: 11099382DOI: 10.1006/jmbi.2000.4236 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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