Related Experiment Video

Updated: Jun 28, 2025

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein
11:23

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein

Published on: June 30, 2019

6.2K

Identification of a Catalytic Lysine Residue Conserved Among GHKL ATPases: MutL, GyrB, and MORC

Kenji Fukui1, Yuki Fujii2, Takato Yano1

  • 1Department of Biochemistry, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan.

Journal of Molecular Biology
|April 19, 2024
PubMed

Insights

Researchers identified a key lysine residue (Lys79) in DNA mismatch repair MutL, crucial for its ATPase activity and potentially impacting Lynch syndrome pathogenicity. This finding advances understanding of DNA repair mechanisms and related hereditary cancers.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • DNA mismatch repair (MMR) endonuclease MutL is vital for genomic stability.
  • Mutations in MutL homologs are linked to hereditary nonpolyposis colorectal cancer, also known as Lynch syndrome.
  • The ATPase activity of MutL is essential for its function, but its catalytic mechanism remains incompletely understood.

Purpose of the Study:

  • To elucidate the catalytic mechanism of the ATPase activity of MutL homologs.
  • To identify the specific amino acid residues involved in catalysis.
  • To provide insights into the pathogenicity of Lynch syndrome-associated mutations.

Main Methods:

  • Characterization of MutL homologs from human and Aquifex aeolicus (aqMutL).
  • Analysis of ATPase activity dependence on pH.
  • Site-directed mutagenesis to identify catalytic residues.

Main Results:

  • pH dependence analysis revealed catalysis by a residue with an alkaline pKa.
  • Lysine 79 (Lys79) in aqMutL was identified as the catalytic residue.
  • Corresponding residues in human MutL homologs were confirmed as critical for activity.
  • The proposed catalytic mechanism for MutL ATPase is conserved in other GHKL ATPases like DNA gyrases.

Conclusions:

  • A novel catalytic mechanism for MutL ATPase activity involving a conserved lysine residue has been proposed.
  • This mechanism provides a basis for evaluating Lynch syndrome-associated missense mutations.
  • The findings have broader implications for understanding other GHKL ATPase superfamily members.
Keywords:
DNA mismatch repairGHKL ATPasesLynch syndromeMORCPMS2

More Related Videos

Metabolic Labeling of Leucine Rich Repeat Kinases 1 and 2 with Radioactive Phosphate11:31

Metabolic Labeling of Leucine Rich Repeat Kinases 1 and 2 with Radioactive Phosphate

Published on: September 18, 2013

10.0K
Assaying the Kinase Activity of LRRK2 in vitro06:09

Assaying the Kinase Activity of LRRK2 in vitro

Published on: January 18, 2012

22.6K

Related Concept Videos

Conserved Binding Sites01:49

Conserved Binding Sites

Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
4.2K
Ligand Binding and Linkage00:49

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.8K
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....
6.8K
Lysosomal Hydrolases01:22

Lysosomal Hydrolases

Lysosomes are the site for the degradation of macromolecules and biological polymers released during membrane trafficking events such as secretory, endocytic, autophagic, and phagocytic pathways. The membrane-enclosed area of the lysosome, called the lumen, contains hydrolytic enzymes active in an acidic environment. These acid hydrolases are functional at a pH between 4.5 and 5 and are involved in cellular processes such as cell signaling, energy metabolism, restoration of the plasma membrane,...
3.8K