Deep-Sea Enzyme Survives Extreme Heat Like a Superhero

Topic: Biology

Scientists in Germany studied an enzyme from a deep-sea microorganism called Methanocaldococcus infernus. They found that this enzyme can work at very high temperatures, above 90°C, and even survives up to 98°C without breaking down.

Microorganisms are amazing chemists. One example is nitrogen fixation, where they convert nitrogen gas (N2) into a form living things can use. Nitrogen makes up about 78% of our atmosphere, but plants and animals can't use it directly because the two nitrogen atoms in N2 are joined by an extremely strong chemical triple bond.

The deep-sea archaeon Methanocaldococcus infernus lives in volcanic marine environments where temperatures can reach above the boiling point of water. Researchers at the Max Planck Institute for Marine Microbiology wanted to understand how this microorganism performs nitrogen fixation under such extreme conditions. They managed to 'tame' the microbe in the lab and made it fix N2 at temperatures above 90°C.

The key enzyme behind this ability is called nitrogenase. It contains a metal-containing helper molecule called a metallocofactor, which binds to enzymes and helps them work. The most studied nitrogenases contain a molybdenum-based metallocofactor, but others use vanadium or only iron.

The team isolated the nitrogenase from Methanocaldococcus infernus and found that it was unusually resistant to heat. It started breaking apart at 90°C, but some of it remained intact even at 98°C. This means that this enzyme is designed to function under conditions where most proteins would quickly decay.

The researchers used a powerful X-ray machine called a synchrotron to study the molecular structure of the enzyme in detail. They found that it was the simplest known example of nitrogenase yet studied, and it combined structural features from all three major nitrogenase families.

Why It Matters

This discovery can help us understand how nature breaks down strong chemical bonds, which is essential for sustainable ammonia production. It can also inspire new technologies to develop enzymes that work under extreme conditions.

Key Facts

• The deep-sea archaeon Methanocaldococcus infernus lives in volcanic marine environments where temperatures can reach above the boiling point of water.
• The key enzyme behind nitrogen fixation is called nitrogenase, which contains a metal-containing helper molecule called a metallocofactor.
• The team isolated the nitrogenase from Methanocaldococcus infernus and found that it was unusually resistant to heat, surviving up to 98°C without breaking down.
• The researchers used a powerful X-ray machine called a synchrotron to study the molecular structure of the enzyme in detail.
• This discovery can help us understand how nature breaks down strong chemical bonds, which is essential for sustainable ammonia production.

Key Terms

nitrogenase

An enzyme that converts nitrogen gas into a form living things can use

metalcofactor

A metal-containing helper molecule that binds to enzymes and helps them work

Implications

This discovery can help us understand how nature breaks down strong chemical bonds, which is essential for sustainable ammonia production. It can also inspire new technologies to develop enzymes that work under extreme conditions.