7K21 image
Deposition Date 2020-09-08
Release Date 2020-11-04
Last Version Date 2025-04-02
Entry Detail
PDB ID:
7K21
Title:
Cryo-EM structure of pyrene-labeled ADP-Pi-actin filaments
Biological Source:
Source Organism:
Gallus gallus (Taxon ID: 9031)
Method Details:
Experimental Method:
Resolution:
3.00 Å
Aggregation State:
FILAMENT
Reconstruction Method:
HELICAL
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Actin, alpha skeletal muscle
Gene (Uniprot):ACTA1
Chain IDs:A, B, C, D
Chain Length:375
Number of Molecules:4
Biological Source:Gallus gallus
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
HIC A HIS modified residue
Primary Citation
Cryo-electron microscopy structures of pyrene-labeled ADP-P i - and ADP-actin filaments.
Nat Commun 11 5897 5897 (2020)
PMID: 33214556 DOI: 10.1038/s41467-020-19762-1

Abstact

Since the fluorescent reagent N-(1-pyrene)iodoacetamide was first used to label skeletal muscle actin in 1981, the pyrene-labeled actin has become the most widely employed tool to measure the kinetics of actin polymerization and the interaction between actin and actin-binding proteins. Here we report high-resolution cryo-electron microscopy structures of actin filaments with N-1-pyrene conjugated to cysteine 374 and either ADP (3.2 Å) or ADP-phosphate (3.0 Å) in the active site. Polymerization buries pyrene in a hydrophobic cavity between subunits along the long-pitch helix with only minor differences in conformation compared with native actin filaments. These structures explain how polymerization increases the fluorescence 20-fold, how myosin and cofilin binding to filaments reduces the fluorescence, and how profilin binding to actin monomers increases the fluorescence.

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Primary Citation of related structures