Structural transitions of F-actin upon ATP hydrolysis at near-atomic resolution revealed by cryo-EM.
Merino, F., Pospich, S., Funk, J., Wagner, T., Kullmer, F., Arndt, H.D., Bieling, P., Raunser, S.(2018) Nat Struct Mol Biol 25: 528-537
- PubMed: 29867215
- DOI: https://doi.org/10.1038/s41594-018-0074-0
- Primary Citation of Related Structures:
5ONV, 5OOC, 5OOD, 5OOE, 5OOF, 6FHL - PubMed Abstract:
The function of actin is coupled to the nucleotide bound to its active site. ATP hydrolysis is activated during polymerization; a delay between hydrolysis and inorganic phosphate (P i ) release results in a gradient of ATP, ADP-P i and ADP along actin filaments (F-actin). Actin-binding proteins can recognize F-actin's nucleotide state, using it as a local 'age' tag. The underlying mechanism is complex and poorly understood. Here we report six high-resolution cryo-EM structures of F-actin from rabbit skeletal muscle in different nucleotide states. The structures reveal that actin polymerization repositions the proposed catalytic base, His161, closer to the γ-phosphate. Nucleotide hydrolysis and P i release modulate the conformational ensemble at the periphery of the filament, thus resulting in open and closed states, which can be sensed by coronin-1B. The drug-like toxin jasplakinolide locks F-actin in an open state. Our results demonstrate in detail how ATP hydrolysis links to F-actin's conformational dynamics and protein interaction.
Organizational Affiliation:
Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.