A Rac1-GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium

The crystal structure of a Rac1-GDP-Zn complex shows that Rac1 can coordinate zinc in a tetrahedral fashion by using residues in its biologically relevant switch I and switch II structural regions. Additionally, zinc can replace the normally coordinated magnesium without the perturbation of GDP from the small GTPase.