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Tetramerization and single-stranded DNA binding properties of native and mutated forms of murine mitochondrial single-stranded DNA-binding proteins.

Publication ,  Journal Article
Li, K; Williams, RS
Published in: J Biol Chem
March 28, 1997

We examined previously unexplored aspects of the tetramerization and single-stranded DNA (ssDNA) binding properties of native, precursor, and mutated forms of mitochondrial ssDNA-binding protein (mtSSB) from a mammalian organism (mouse). Tetramic forms of mtSSB reassemble spontaneously after thermal denaturation and undergo subunit exchange. Binding of mtSSB to ssDNA as a function of protein concentration is nonlinear, suggesting a concentration-dependent transition in intrinsic binding affinity and in the topology of the DNA-protein complex. The cleavable presequence at the amino terminus of the precursor form of mtSSB does not disrupt tetramer formation but has a specific inhibitory effect on DNA binding that is not seen in a fusion protein that substitutes a bulkier peptide moiety in this position. Mutated forms of mtSSB bearing amino acid substitutions at highly conserved amino acid positions exhibit subtle or severe defects in ssDNA binding activity and/or tetramerization, even when assembled into heterotetramers in combination with wild-type mtSSB monomers. These experiments provide new insights into structural and functional properties of mammalian mtSSB and have implications for the pathogenesis of human diseases resulting from defects in mtDNA replication.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 28, 1997

Volume

272

Issue

13

Start / End Page

8686 / 8694

Location

United States

Related Subject Headings

  • Xenopus Proteins
  • Xenopus
  • Saccharomyces cerevisiae
  • Recombinant Fusion Proteins
  • Protein Denaturation
  • Protein Conformation
  • Polymerase Chain Reaction
  • Mutagenesis, Site-Directed
  • Molecular Sequence Data
  • Mice
 

Citation

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Li, K., & Williams, R. S. (1997). Tetramerization and single-stranded DNA binding properties of native and mutated forms of murine mitochondrial single-stranded DNA-binding proteins. J Biol Chem, 272(13), 8686–8694. https://doi.org/10.1074/jbc.272.13.8686
Li, K., and R. S. Williams. “Tetramerization and single-stranded DNA binding properties of native and mutated forms of murine mitochondrial single-stranded DNA-binding proteins.J Biol Chem 272, no. 13 (March 28, 1997): 8686–94. https://doi.org/10.1074/jbc.272.13.8686.
Li, K., and R. S. Williams. “Tetramerization and single-stranded DNA binding properties of native and mutated forms of murine mitochondrial single-stranded DNA-binding proteins.J Biol Chem, vol. 272, no. 13, Mar. 1997, pp. 8686–94. Pubmed, doi:10.1074/jbc.272.13.8686.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 28, 1997

Volume

272

Issue

13

Start / End Page

8686 / 8694

Location

United States

Related Subject Headings

  • Xenopus Proteins
  • Xenopus
  • Saccharomyces cerevisiae
  • Recombinant Fusion Proteins
  • Protein Denaturation
  • Protein Conformation
  • Polymerase Chain Reaction
  • Mutagenesis, Site-Directed
  • Molecular Sequence Data
  • Mice