Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 8-mer - A7B1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 316.40 kDa 
• Atom Count: 21690 
• Residue Count: 2754 
• Unique protein chains: 2

6UC0

Isolated S3D-cofilin bound to an actin filament

• DOI: 10.2210/pdb6UC0/pdb
• EMDataResource: EMD-20724

• Classification: STRUCTURAL PROTEIN
• Organism(s): Homo sapiens, Oryctolagus cuniculus
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2019-09-13 Released: 2020-01-01 
• Deposition Author(s): Huehn, A.R., Bibeau, J.P., Schramm, A.C., Cao, W., De La Cruz, E.M., Sindelar, C.V.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 7.50 Å
• Aggregation State: HELICAL ARRAY 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Structures of cofilin-induced structural changes reveal local and asymmetric perturbations of actin filaments.

Huehn, A.R., Bibeau, J.P., Schramm, A.C., Cao, W., De La Cruz, E.M., Sindelar, C.V.

(2020) Proc Natl Acad Sci U S A 117: 1478-1484

• PubMed: 31900364 
• DOI: 10.1073/pnas.1915987117
• Primary Citation of Related Structures:  
  6VAU, 6VAO, 6UC4, 6UBY, 6UC0


• PubMed Abstract: 
  

Members of the cofilin/ADF family of proteins sever actin filaments, increasing the number of filament ends available for polymerization or depolymerization. Cofilin binds actin filaments with positive cooperativity, forming clusters of contiguously bound cofilin along the filament lattice. Filament severing occurs preferentially at boundaries between bare and cofilin-decorated (cofilactin) segments and is biased at 1 side of a cluster. A molecular understanding of cooperative binding and filament severing has been impeded by a lack of structural data describing boundaries. Here, we apply methods for analyzing filament cryo-electron microscopy (cryo-EM) data at the single subunit level to directly investigate the structure of boundaries within partially decorated cofilactin filaments. Subnanometer resolution maps of isolated, bound cofilin molecules and an actin-cofilactin boundary indicate that cofilin-induced actin conformational changes are local and limited to subunits directly contacting bound cofilin. An isolated, bound cofilin compromises longitudinal filament contacts of 1 protofilament, consistent with a single cofilin having filament-severing activity. An individual, bound phosphomimetic (S3D) cofilin with weak severing activity adopts a unique binding mode that does not perturb actin structure. Cofilin clusters disrupt both protofilaments, consistent with a higher severing activity at boundaries compared to single cofilin. Comparison of these structures indicates that this disruption is substantially greater at pointed end sides of cofilactin clusters than at the barbed end. These structures, with the distribution of bound cofilin clusters, suggest that maximum binding cooperativity is achieved when 2 cofilins occupy adjacent sites. These results reveal the structural origins of cooperative cofilin binding and actin filament severing.

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Organizational Affiliation: 

Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 [e-mail] [e-mail].

Macromolecules

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Cofilin-1	I	166	Homo sapiens	Mutation(s): 1  Gene Names: CFL1, CFL
Find proteins for P23528 (Homo sapiens) Explore P23528  Go to UniProtKB:  P23528
NIH Common Fund Data Resources
PHAROS  P23528 GTEx  ENSG00000172757

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Actin, alpha skeletal muscle	A, B, C, D, E, F, G	377	Oryctolagus cuniculus	Mutation(s): 0  Gene Names: ACTA1, ACTA
Find proteins for P68135 (Oryctolagus cuniculus) Explore P68135  Go to UniProtKB:  P68135

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ADP	A, B, C, D, E, F, G	ADENOSINE-5'-DIPHOSPHATE C10 H15 N5 O10 P2 XTWYTFMLZFPYCI-KQYNXXCUSA-N
MG	A, B, C, D, E, F, G	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 7.50 Å
• Aggregation State: HELICAL ARRAY 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History & Funding Information

Deposition Data

• Deposited Date: 2019-09-13 
• Released Date: 2020-01-01 
Deposition Author(s): Huehn, A.R., Bibeau, J.P., Schramm, A.C., Cao, W., De La Cruz, E.M., Sindelar, C.V.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	GM097348
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	GM110533001

Revision History 

• Version 1.0: 2020-01-01
  Type: Initial release
  
• Version 1.1: 2020-01-15
  Changes: Database references
• Version 1.2: 2020-02-05
  Changes: Database references