Download MendeleyA Rac1-GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium.
Prehna, G., Stebbins, C.E.(2007) Acta Crystallogr D Biol Crystallogr 63: 628-635
- PubMed: 17452788
- DOI: https://doi.org/10.1107/S0907444907010888
- Primary Citation of Related Structures:
2P2L - PubMed Abstract:
The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3(2)21 and its crystal structure has been solved at 1.9 A resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.
Organizational Affiliation:
Laboratory of Structural Microbiology, Rockefeller University, New York, NY 10021, USA.
