Related Experiment Video
Updated: Jun 5, 2026
11:27
X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Structure-function relationship in an archaebacterial methionine sulphoxide reductase B
Michela Carella1, Juliane Becher, Oliver Ohlenschläger
1Leibniz-Institut für Altersforschung Fritz-Lipmann-Institut, Beutenbergstr. 11, D-07745 Jena, Germany.
Molecular Microbiology
|January 12, 2011
Summary
Methionine sulphoxide reductases (MSRs) repair oxidized methionine. This study details the structure and activity of MTH711, a zinc-containing MSRB from Methanothermobacter thermoautotrophicus, revealing a unique reaction mechanism.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Methionine oxidation to methionine sulphoxide (MetSO) can impair molecular function.
- Methionine sulphoxide reductases (MSRs) catalyze the repair of MetSO to methionine.
- Two classes of MSRs, MSRA and MSRB, exist with distinct stereoselectivity.
Purpose of the Study:
- To characterize the activity and NMR structure of MTH711, a MSRB from Methanothermobacter thermoautotrophicus.
- To investigate the structural and functional properties of a zinc-containing MSRB from an anaerobic archaeon.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy was used to determine the structure of MTH711.
- Enzyme activity assays were performed to study the catalytic properties of MTH711.
- Comparative structural analysis was conducted with other MSRB enzymes.
Main Results:
- MTH711, a zinc-containing MSRB, was structurally characterized from Methanothermobacter thermoautotrophicus.
- The enzyme exhibits a more rigid structure compared to MSRBs from aerobic organisms.
- NMR data revealed no significant structural differences between oxidized and reduced MTH711 states, with a stable sulphenic acid intermediate at the catalytic cysteine.
Conclusions:
- MTH711's catalytic mechanism appears distinct from other characterized MSRBs.
- Non-zinc-binding cysteines are not essential for MTH711 activity.
- The findings provide insights into the evolution and diversity of methionine repair pathways in anaerobic archaea.
Related Concept Videos
01:20Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
01:46Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
01:41The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
01:24Nucleoid
The nucleoid represents a structurally and functionally distinct region within prokaryotic cells, where the cell's DNA and associated proteins are housed. Unlike eukaryotic cells, prokaryotes lack a membrane-bound nucleus, and the nucleoid facilitates the organization and accessibility of the genetic material within this constraint. The DNA in most bacteria and archaea exists as a single, circular, double-stranded molecule that is highly compacted through supercoiling and interactions with...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
01:27Diversity of Archaea III
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...