8a2u | pdb_00008a2u

Cryo-EM structure of F-actin in the Ca2+-ADP-BeF3- nucleotide state.

spinqualitylabelsall models 8a2u, resolution 2.21Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8a2u is a 5 chain structure with sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ADP, BEF, CA, HIC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ACTS_RABIT Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. Publication Abstract from PubMed The dynamic turnover of actin filaments (F-actin) controls cellular motility in eukaryotes and is coupled to changes in the F-actin nucleotide state<sup>1-3</sup>. It remains unclear how F-actin hydrolyses ATP and subsequently undergoes subtle conformational rearrangements that ultimately lead to filament depolymerization by actin-binding proteins. Here we present cryo-electron microscopy structures of F-actin in all nucleotide states, polymerized in the presence of Mg<sup>2+</sup> or Ca<sup>2+</sup> at approximately 2.2 A resolution. The structures show that actin polymerization induces the relocation of water molecules in the nucleotide-binding pocket, activating one of them for the nucleophilic attack of ATP. Unexpectedly, the back door for the subsequent release of inorganic phosphate (P<sub>i</sub>) is closed in all structures, indicating that P<sub>i</sub> release occurs transiently. The small changes in the nucleotide-binding pocket after ATP hydrolysis and P<sub>i</sub> release are sensed by a key amino acid, amplified and transmitted to the filament periphery. Furthermore, differences in the positions of water molecules in the nucleotide-binding pocket explain why Ca<sup>2+</sup>-actin shows slower polymerization rates than Mg<sup>2+</sup>-actin. Our work elucidates the solvent-driven rearrangements that govern actin filament assembly and aging and lays the foundation for the rational design of drugs and small molecules for imaging and therapeutic applications. Structural basis of actin filament assembly and aging.,Oosterheert W, Klink BU, Belyy A, Pospich S, Raunser S Nature. 2022 Nov;611(7935):374-379. doi: 10.1038/s41586-022-05241-8. Epub 2022, Oct 26. PMID:36289337 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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