Related Experiment Video

Updated: Aug 20, 2026

Preparation of Mycobacterium tuberculosis Culture Filtrate to Understand TB Pathogenesis
07:32

Preparation of Mycobacterium tuberculosis Culture Filtrate to Understand TB Pathogenesis

Published on: March 28, 2025

Characterization of a Mycobacterium tuberculosis proteasomal ATPase homologue

K Heran Darwin1, Gang Lin, Zhiqiang Chen

  • 1Department of Microbiology and Immunology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA. heran.darwin@med.nyu.edu

Molecular Microbiology
|January 22, 2005
PubMed

Insights

Mycobacterium tuberculosis proteasome ATPase (Mpa) is crucial for protection against reactive nitrogen intermediates. Its enzymatic activity is necessary but not sufficient for this protection, impacting bacterial virulence.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • Reactive nitrogen intermediates (RNIs) pose a significant threat to Mycobacterium tuberculosis (Mtb) survival.
  • The Mtb proteasome and its ATPase components are implicated in cellular stress responses.

Purpose of the Study:

  • To investigate the role of the presumptive proteasomal ATPase gene mpa (Rv2115c) in Mtb's resistance to RNIs.
  • To characterize the enzymatic activity of Mpa and its contribution to Mtb virulence.

Main Methods:

  • Genetic screening to identify Mtb mutants sensitive to RNIs.
  • Biochemical assays to assess Mpa ATPase activity in vitro.
  • In vivo virulence studies in mouse models.

Main Results:

  • Transposon insertions in mpa conferred sensitivity to RNIs.
  • Mpa is an AAA ATPase forming hexameric rings, similar to eukaryotic VCP.
  • Mutations in conserved ATPase motifs abolished Mpa activity and protection against nitrite.
  • A C-terminal truncation mutant retained ATPase activity but lost protective function.

Conclusions:

  • Mpa's ATPase activity is essential for Mtb protection against RNIs.
  • Enzymatic activity alone is insufficient; other factors are required for full protection.
  • Mpa plays a critical role in Mtb virulence and survival under oxidative stress.

More Related Videos

Separation and Fractionation of Cell Wall and Cell Membrane Proteins from Mycobacterium tuberculosis for Downstream Protein Analysis06:14

Separation and Fractionation of Cell Wall and Cell Membrane Proteins from Mycobacterium tuberculosis for Downstream Protein Analysis

Published on: September 26, 2025

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep105011:27

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050

Published on: May 13, 2020

Related Concept Videos

The Proteasome Structure01:17

The Proteasome Structure

The ubiquitin-proteasome pathway is a well-known mechanism utilized by eukaryotic cells to remove cytoplasmic proteins that are misfolded, damaged, or no longer needed. In this pathway, the protein that needs to be eliminated undergoes a process called ubiquitination, where a chain of ubiquitin molecules is attached to the 48th lysine residue of the target protein. This ubiquitin modification helps the proteasome distinguish between a target protein and a healthy protein.
The proteasome is an...
The Proteasome01:13

The Proteasome

Eukaryotic cells can degrade proteins through several pathways. One of the most important among these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
The Proteasome02:18

The Proteasome

Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
Allosteric Proteins-ATCase01:19

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function.  For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to  N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Energy to Drive Translocation01:37

Energy to Drive Translocation

Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Protein Complex Assembly02:41

Protein Complex Assembly

Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types.  Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...