6ANU

Cryo-EM structure of F-actin complexed with the beta-III-spectrin actin-binding domain

Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 7.00 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history. 


Literature

Structural basis for high-affinity actin binding revealed by a beta-III-spectrin SCA5 missense mutation.

Avery, A.W., Fealey, M.E., Wang, F., Orlova, A., Thompson, A.R., Thomas, D.D., Hays, T.S., Egelman, E.H.

(2017) Nat Commun 8: 1350-1350

  • DOI: 10.1038/s41467-017-01367-w
  • Primary Citation of Related Structures:  
    6ANU

  • PubMed Abstract: 

    • Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the cytoskeletal protein β-III-spectrin. Previously, a SCA5 mutation resulting in a leucine-to-proline substitution (L253P) in the actin-binding domain (ABD) w ...

    Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the cytoskeletal protein β-III-spectrin. Previously, a SCA5 mutation resulting in a leucine-to-proline substitution (L253P) in the actin-binding domain (ABD) was shown to cause a 1000-fold increase in actin-binding affinity. However, the structural basis for this increase is unknown. Here, we report a 6.9 Å cryo-EM structure of F-actin complexed with the L253P ABD. This structure, along with co-sedimentation and pulsed-EPR measurements, demonstrates that high-affinity binding caused by the CH2-localized mutation is due to opening of the two CH domains. This enables CH1 to bind actin aided by an unstructured N-terminal region that becomes α-helical upon binding. This helix is required for association with actin as truncation eliminates binding. Collectively, these results shed light on the mechanism by which β-III-spectrin, and likely similar actin-binding proteins, interact with actin, and how this mechanism can be perturbed to cause disease.

    Organizational Affiliation: 

    Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Actin, cytoplasmic 1A, B, C, D, E, F375Homo sapiensMutation(s): 0 
Gene Names: ACTB
Find proteins for P60709 (Homo sapiens)
Explore P60709 
Go to UniProtKB:  P60709
NIH Common Fund Data Resources
PHAROS  P60709
GTEx  ENSG00000075624
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  • Reference Sequence
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Spectrin beta chain, non-erythrocytic 2a, b, c, d, e, f284Homo sapiensMutation(s): 1 
Gene Names: SPTBN2, KIAA0302, SCA5
Find proteins for O15020 (Homo sapiens)
Explore O15020 
Go to UniProtKB:  O15020
NIH Common Fund Data Resources
PHAROS  O15020
GTEx  ENSG00000173898
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 7.00 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM81303
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM44757
National Institutes of Health/National Institute on Aging (NIH/NIA)United StatesAG32961

Revision History 

  • Version 1.0: 2017-11-22
    Type: Initial release
  • Version 1.1: 2019-12-18
    Changes: Author supporting evidence