6ANU

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


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 7 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

wwPDB Validation 3D Report Full Report


This is version 1.0 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

  • 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 Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Actin, cytoplasmic 1
F, A, B, C, D, E
375Homo sapiensGene Names: ACTB
Find proteins for P60709 (Homo sapiens)
Go to Gene View: ACTB
Go to UniProtKB:  P60709
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Spectrin beta chain, non-erythrocytic 2
f, a, b, c, d, e
284Homo sapiensGene Names: SPTBN2 (KIAA0302, SCA5)
Find proteins for O15020 (Homo sapiens)
Go to Gene View: SPTBN2
Go to UniProtKB:  O15020
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 7 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 
Software Package:
Software NamePurpose
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationCountryGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM81303
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM44757
National Institutes of Health/National Institute on AgingUnited StatesAG32961

Revision History 

  • Version 1.0: 2017-11-22
    Type: Initial release