Related Experiment Video

Updated: May 30, 2025

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein
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Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Published on: March 31, 2010

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The mismatch repair factor Mlh1-Pms1 uses ATP to compact and remodel DNA

Bryce W Collingwood1, Amruta N Bhalkar1, Carol M Manhart1

  • 1Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, USA.

Biorxiv : the Preprint Server for Biology
|January 27, 2025
PubMed

Insights

DNA mismatch repair uses MutS homolog (MSH) complexes and Mlh1-Pms1/PMS2 to fix errors. Mlh1-Pms1

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Eukaryotic DNA mismatch repair initiates with MutS homolog (MSH) complexes scanning newly replicated DNA.
  • MSH complexes recruit Mlh1-Pms1/PMS2 (yeast/human) endonuclease upon mismatch detection, which nicks DNA for downstream processing.
  • Mlh1-Pms1 is an ATPase, but ATP is not required for DNA nicking, suggesting a regulatory role.

Purpose of the Study:

  • To investigate the role of Mlh1-Pms1's ATPase activity in DNA mismatch repair.
  • To explore how non-B-form DNA structures affect Mlh1-Pms1 function.
  • To understand the interplay between DNA structure and mismatch repair mechanisms.

Main Methods:

  • Utilized yeast as a model organism.
  • Investigated Mlh1-Pms1 oligomerization and DNA conformational changes.
  • Assessed Mlh1-Pms1 activity in the presence of non-B-form DNA structures.

Main Results:

  • Mlh1-Pms1 forms oligomeric complexes that induce DNA conformational rearrangements via its ATPase activity.
  • Non-B-form DNA structures, prevalent in microsatellite regions, inhibit Mlh1-Pms1's activities.
  • Inhibition is likely due to impeded Mlh1-Pms1-dependent DNA conformational changes.

Conclusions:

  • Mlh1-Pms1's ATPase activity is crucial for driving DNA conformational changes during mismatch repair.
  • Non-B-form DNA structures can impair mismatch repair by hindering these DNA rearrangements.
  • DNA compaction and topology significantly influence Mlh1-Pms1 function and mismatch repair efficiency, potentially explaining genomic instability in microsatellite regions.

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