Related Experiment Video

Updated: Sep 29, 2026

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein
11:01

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

Published on: March 31, 2010

DNA binding properties of the yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers

Karin Drotschmann1, Mark C Hall, Polina V Shcherbakova

  • 1Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.

Biological Chemistry
|September 12, 2002
PubMed

Insights

DNA repair proteins Msh2-Msh6 and Mlh1-Pms1 have distinct DNA binding properties. Msh2-Msh6 recognizes mismatches, while Mlh1-Pms1 exhibits cooperative binding, potentially impacting DNA repair and cellular signaling.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • DNA mismatch repair (MMR) is crucial for genomic stability.
  • Msh2-Msh6 and Mlh1-Pms1 are key protein complexes in the MMR pathway.
  • Understanding their DNA binding is essential for elucidating MMR mechanisms.

Purpose of the Study:

  • To investigate the DNA binding properties of Msh2-Msh6 and Mlh1-Pms1.
  • To determine how these complexes interact with DNA during mismatch repair.
  • To explore potential roles of Mlh1-Pms1 DNA binding in other cellular processes.

Main Methods:

  • Site-directed mutagenesis of Msh2-Msh6 based on crystal structure.
  • Biochemical assays to study DNA binding affinities and preferences.
  • Atomic force microscopy (AFM) to visualize Mlh1-Pms1-DNA interactions.

Main Results:

  • Specific amino acid side chains in Msh2-Msh6 are critical for binding to mismatched DNA.
  • Msh6 side chains likely stabilize a kinked DNA conformation via stacking and hydrogen bonding.
  • Mlh1-Pms1 binds DNA independently of mismatches, showing cooperative binding to duplex DNA and preference for single-stranded DNA.
  • AFM revealed cooperative binding and simultaneous interaction with two DNA duplexes by Mlh1-Pms1.

Conclusions:

  • Msh2-Msh6 utilizes specific DNA backbone contacts for mismatch recognition and repair initiation.
  • Mlh1-Pms1 exhibits unique cooperative DNA binding properties.
  • The novel DNA binding characteristics of Mlh1-Pms1 may be important for signal transduction in MMR, recombination, meiosis, and DNA damage responses.

More Related Videos

Isolating Interaction-Null/Impaired Mutants Using the Yeast Two-Hybrid Assay02:44

Isolating Interaction-Null/Impaired Mutants Using the Yeast Two-Hybrid Assay

Published on: December 29, 2023

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy11:40

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy

Published on: June 25, 2013

Related Concept Videos

Protein Complexes with Interchangeable Parts01:57

Protein Complexes with Interchangeable Parts

Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
Mismatch Repair01:48

Mismatch Repair

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.The Mutator Protein Family Plays a Key Role in DNA Mismatch RepairThe human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
Mismatch Repair01:20

Mismatch Repair

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
Single-Strand DNA Binding Proteins01:03

Single-Strand DNA Binding Proteins

For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
Yeast Signaling01:41

Yeast Signaling

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.