Crystal Structure of the N-terminal region of AlphaII-spectrin Tetramerization Domain

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.220 

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Crystal structure of the nonerythroid alpha-spectrin tetramerization site reveals differences between erythroid and nonerythroid spectrin tetramer formation.

Mehboob, S.Song, Y.Witek, M.Long, F.Santarsiero, B.D.Johnson, M.E.Fung, L.W.

(2010) J Biol Chem 285: 14572-14584

  • DOI: https://doi.org/10.1074/jbc.M109.080028
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We have solved the crystal structure of a segment of nonerythroid alpha-spectrin (alphaII) consisting of the first 147 residues to a resolution of 2.3 A. We find that the structure of this segment is generally similar to a corresponding segment from erythroid alpha-spectrin (alphaI) but exhibits unique differences with functional significance. Specific features include the following: (i) an irregular and frayed first helix (Helix C'); (ii) a helical conformation in the junction region connecting Helix C' with the first structural domain (D1); (iii) a long A(1)B(1) loop in D1; and (iv) specific inter-helix hydrogen bonds/salt bridges that stabilize D1. Our findings suggest that the hydrogen bond networks contribute to structural domain stability, and thus rigidity, in alphaII, and the lack of such hydrogen bond networks in alphaI leads to flexibility in alphaI. We have previously shown the junction region connecting Helix C' to D1 to be unstructured in alphaI (Park, S., Caffrey, M. S., Johnson, M. E., and Fung, L. W. (2003) J. Biol. Chem. 278, 21837-21844) and now find it to be helical in alphaII, an important difference for alpha-spectrin association with beta-spectrin in forming tetramers. Homology modeling and molecular dynamics simulation studies of the structure of the tetramerization site, a triple helical bundle of partial domain helices, show that mutations in alpha-spectrin will affect Helix C' structural flexibility and/or the junction region conformation and may alter the equilibrium between spectrin dimers and tetramers in cells. Mutations leading to reduced levels of functional tetramers in cells may potentially lead to abnormal neuronal functions.

  • Organizational Affiliation

    Center for Pharmaceutical Biotechnology, University of Illinois at Chicago, Chicago, Illinois 60607, USA. shahila@uic.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Spectrin alpha chain, brain
A, B
149Homo sapiensMutation(s): 0 
Gene Names: SPTAN1SPTA2
UniProt & NIH Common Fund Data Resources
Find proteins for Q13813 (Homo sapiens)
Explore Q13813 
Go to UniProtKB:  Q13813
PHAROS:  Q13813
GTEx:  ENSG00000197694 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ13813
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.220 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.72α = 90
b = 71.46β = 90
c = 80.81γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
HYSS/RESOLVEmodel building
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-10-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Author supporting evidence
  • Version 1.3: 2023-12-27
    Changes: Data collection, Database references