1SQK

CRYSTAL STRUCTURE OF CIBOULOT IN COMPLEX WITH SKELETAL ACTIN

Summary for 1SQK

• Entry DOI: 10.2210/pdb1sqk/pdb
• Descriptor: ACTIN, ALPHA SKELETAL MUSCLE, CIBOULOT, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: ciboulot; wh2 domain; actin; actin-binding protein, structural protein-protein binding complex, structural protein/protein binding
• Biological source: Drosophila melanogaster (fruit fly); More
• Cellular location: Cytoplasm, cytoskeleton: P68135
• Total number of polymer chains: 2
• Total formula weight: 45761.13

Authors

Hertzog, M.,Van Heijenoort, C.,Didry, D.,Gaudier, M.,Gigant, B.,Coutant, J.,Didelot, G.,Preat, T.,Knossow, M.,Guittet, E.,Carlier, M.F. (deposition date: 2004-03-19, release date: 2004-06-15, Last modification date: 2023-08-23)

Primary citation

Hertzog, M.,Van Heijenoort, C.,Didry, D.,Gaudier, M.,Coutant, J.,Gigant, B.,Didelot, G.,Knossow, M.,Guittet, E.,Carlier, M.F.
The beta-Thymosin/WH2 Domain; Structural Basis for the Switch from Inhibition to Promotion of Actin Assembly
Cell(Cambridge,Mass.), 117:611-623, 2004

PubMed Abstract: The widespread beta-thymosin/WH2 actin binding domain has versatile regulatory properties in actin dynamics and motility. beta-thymosins (isolated WH2 domain) maintain monomeric actin in a "sequestered" nonpolymerizable form. In contrast, when repeated in tandem or inserted in modular proteins, the beta-thymosin/WH2 domain promotes actin assembly at filament barbed ends, like profilin. The structural basis for these opposite functions is addressed using ciboulot, a three beta-thymosin repeat protein. Only the first repeat binds actin and possesses the function of ciboulot. The region that shows the strongest interaction with actin is an amphipathic N-terminal alpha helix, present in all beta-thymosin/WH2 domains, which recognizes the ATP bound actin structure and uses the shear motion of actin linked to ATP hydrolysis to control polymerization. Crystallographic ((1)H, (15)N), NMR, and mutagenetic data reveal that the weaker interaction of the C-terminal region of beta-thymosin/WH2 domain with actin accounts for the switch in function from inhibition to promotion of actin assembly.

PubMed: 15163409
DOI: 10.1016/S0092-8674(04)00403-9

Experimental method

X-RAY DIFFRACTION (2.5 Å)