Related Experiment Videos
Integrating three views of Arf1 activation dynamics
Charles H Robert1, Jacqueline Cherfils, Liliane Mouawad
1Modélisation et Ingénierie des Protéines, CNRS UMR 8619, Bât. 430, Université de Paris-Sud 91405 Orsay, France.
Journal of Molecular Biology
|March 23, 2004
Summary
The Sec7 family proteins Arno and Gea2 facilitate GDP-GTP exchange on Arf1, a key protein for vesicle transport. Conformational dynamics in these proteins are crucial for efficient nucleotide exchange.
Area of Science:
- Molecular Biology
- Cell Biology
- Structural Biology
Background:
- Proteins Arno and Gea2, part of the Sec7 family, regulate Arf1 activity.
- Arf1 is a small GTP-binding protein essential for intracellular protein transport via coated vesicles.
- Sec7 domain (Sec7d) conformational dynamics are implicated in nucleotide exchange.
Purpose of the Study:
- To investigate the role of conformational dynamics in Sec7 family proteins during Arf1 nucleotide exchange.
- To compare the movements of unbound Sec7 domains and Arf1-GDP with the Arf1-Sec7d complex.
Main Methods:
- Utilized normal modes analyses based on complementary crystal structures.
- Analyzed collective movements of unbound Gea2 and Arno Sec7 domains, Arf1-GDP, and the Arf1-Gea2(Sec7d) complex.
Main Results:
- Unbound Sec7d exhibits low-energy movements leading to hydrophobic groove closure, a conserved feature.
- Arf1-GDP movements involve switch 1 and 2 residues, linked to the N-terminal helix binding site.
- Arf1-Sec7d complex shows large-scale movements facilitating Glu finger insertion for GDP release.
Conclusions:
- Sec7d groove closure is a general mechanism in the Sec7 family.
- Protein dynamics facilitate Arf1-GDP extraction and interswitch movement, crucial for membrane-linked exchange.
- Collective movements in the complex drive nucleotide release, essential for Arf1 activation.