The nature of the globular- to fibrous-actin transition.
Oda, T., Iwasa, M., Aihara, T., Maeda, Y., Narita, A.(2009) Nature 457: 441-445
- PubMed: 19158791 
- DOI: https://doi.org/10.1038/nature07685
- Primary Citation of Related Structures:  
2ZWH - PubMed Abstract: 
Actin plays crucial parts in cell motility through a dynamic process driven by polymerization and depolymerization, that is, the globular (G) to fibrous (F) actin transition. Although our knowledge about the actin-based cellular functions and the molecules that regulate the G- to F-actin transition is growing, the structural aspects of the transition remain enigmatic. We created a model of F-actin using X-ray fibre diffraction intensities obtained from well oriented sols of rabbit skeletal muscle F-actin to 3.3 A in the radial direction and 5.6 A along the equator. Here we show that the G- to F-actin conformational transition is a simple relative rotation of the two major domains by about 20 degrees. As a result of the domain rotation, the actin molecule in the filament is flat. The flat form is essential for the formation of stable, helical F-actin. Our F-actin structure model provides the basis for understanding actin polymerization as well as its molecular interactions with actin-binding proteins.
Organizational Affiliation: 
X-ray Structural Analysis Research Team, RIKEN SPring-8 Center, RIKEN Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan. toda@spring8.or.jp