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Simultaneous Mapping and Quantitation of Ribonucleotides in Human Mitochondrial DNA
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Simultaneous Mapping and Quantitation of Ribonucleotides in Human Mitochondrial DNA

Published on: November 14, 2017

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Structural insights into DNA degradation by human mitochondrial nuclease MGME1

Chun Yang1, Ruiqi Wu1, Hehua Liu1,2

  • 1State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China.

Nucleic Acids Research
|September 25, 2018
PubMed

Insights

Mitochondrial DNA maintenance is crucial, and mutations in the MGME1 enzyme cause severe syndromes. This study reveals the structure of MGME1, clarifying its DNA binding and unwinding mechanisms for potential therapeutic targets.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • Mitochondrial DNA (mtDNA) maintenance and metabolism are vital for cellular function.
  • Mutations in the MGME1 gene cause severe mitochondrial disorders.
  • Human MGME1 is a mitochondria-specific DNase, making it a potential therapeutic target.

Purpose of the Study:

  • To elucidate the molecular mechanisms of human MGME1 (HsMGME1) in mtDNA maintenance.
  • To determine the structural basis of HsMGME1's DNA binding and unwinding activities.
  • To provide insights into the substrate specificity and cleavage directionality of HsMGME1.

Main Methods:

  • X-ray crystallography to determine the structures of HsMGME1 complexes.
  • In vitro cleavage assays to study enzyme activity.
  • Structural comparison with homologous proteins (RecBCD, AddAB).

Main Results:

  • Reported one HsMGME1-Mn2+ complex and three HsMGME1-DNA complex structures.
  • Revealed the detailed molecular basis for substrate DNA binding and unwinding by HsMGME1.
  • Clarified the conserved two-cation-assisted catalytic mechanism and cleavage directionalities.

Conclusions:

  • Structural insights into HsMGME1 provide a foundation for understanding its role in mtDNA maintenance.
  • HsMGME1's unique structure and function offer potential for targeted therapeutic strategies for mitochondrial diseases.
  • Comparison with RecBCD and AddAB highlights conserved and distinct features in DNA double-strand break repair mechanisms.

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