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The membrane-binding domain of ankyrin contains four independently folded subdomains, each comprised of six ankyrin repeats.

Publication ,  Journal Article
Michaely, P; Bennett, V
Published in: J Biol Chem
October 25, 1993

Ankyrin repeats are a 33-amino acid motif present in a number of proteins of diverse functions including transcription factors, cell differentiation molecules, and structural proteins. This motif has been shown to mediate protein interactions in the case of ankyrin as well as several other repeat-bearing proteins. In ankyrin, 24 tandemly arrayed repeats are arranged to form a globular, membrane-binding domain. This report provides evidence that the repeats in this domain fold into four independently folded subdomains of six repeats each. Limited proteolytic digestions of defined regions of the membrane-binding domain identified protease-sensitive sites, which divided this domain into subdomains of approximately six repeats each. Hydrodynamic measurements and circular dichroism spectroscopy of expressed subdomains confirmed that these six-repeat regions exist as folded, globular structures. The requirement of a complete set of six repeats for proper folding was determined using a series of protein constructs, which sequentially deleted repeats from the last subdomain. Deletion of even one repeat resulted in a 40% loss of alpha-helicity. Deletions removing three or more repeats abolished the helical signal completely. The spherical shapes of the intact domain and of the subdomains (inferred from hydrodynamic values) suggest that the four subdomains are organized in either a tetrahedral or square planar configuration. Two six-repeat subdomains were found to be required for high affinity association with the anion exchanger, suggesting that at least some of the protein interactions mediated by ankyrin repeats involve multiple subdomains.

Duke Scholars

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

October 25, 1993

Volume

268

Issue

30

Start / End Page

22703 / 22709

Location

United States

Related Subject Headings

  • Sequence Deletion
  • Repetitive Sequences, Nucleic Acid
  • Recombinant Proteins
  • Protein Structure, Secondary
  • Protein Folding
  • Protein Conformation
  • Mutagenesis
  • Molecular Sequence Data
  • Macromolecular Substances
  • Kinetics
 

Citation

APA
Chicago
ICMJE
MLA
NLM

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

October 25, 1993

Volume

268

Issue

30

Start / End Page

22703 / 22709

Location

United States

Related Subject Headings

  • Sequence Deletion
  • Repetitive Sequences, Nucleic Acid
  • Recombinant Proteins
  • Protein Structure, Secondary
  • Protein Folding
  • Protein Conformation
  • Mutagenesis
  • Molecular Sequence Data
  • Macromolecular Substances
  • Kinetics