Freeze: Scientists film protein in action

April 19, 2007
The film shows how the lysine amino acid (yellow part of the protein) grabs a water molecule (in blue) and imports it into the enzyme to perform the catalytic reaction on the superoxide (in red). Credits: Gergely Katona.

It is difficult to find similarities between Grenoble and Hollywood or between the researchers at the ESRF and the Institut de Biologie Structural (IBS) and world-known filmmakers. However, scientists from these institutes based in Grenoble (France) have managed to produce a movie. The actors are not celebrities but a protein whose role is to eliminate toxic molecules. They filmed this protein in action by freezing it at several states. They publish their results this week in Science.

Most of the research done on proteins is based on their study in a resting state and their study in movement is extremely limited due to technological limitations. Today, a French team has made a movie of an enzyme (a protein that catalyses chemical reactions) found in bacteria.

“The achievement of this research is two-fold: on one hand there is the technological success of filming an enzyme in action and on the other hand there are the results that contribute to the knowledge of how this enzyme works”, explains Dominique Bourgeois, corresponding author for the paper.

The enzyme filmed in action is called “superoxide reductase”, its role is to eliminate a toxic molecule called “superoxide radical”. In order to survive, all living organisms have to fight oxidative stress, produced by outflows of the oxygen metabolism. In humans, about 2% of the oxygen used to breathe is transformed into this toxic “superoxide radical” molecule, instead of water. This production is increased in people affected by neurodegenerative diseases such as Alzheimer. A high amount of these molecules worsen these illnesses, so scientists are looking for drugs to eliminate them.

The enzyme studied by the team acts uniquely in bacteria and its counterpart in humans is more complex. Synthesizing an enzyme like the one studied through biomimetics is an exciting possibility for developing future drugs.

In order to produce the film, the team used the ESRF-IBS “Cryobench” laboratory to freeze the protein in three different states while the reaction took place. In order to make sure that they “trapped” the right intermediate states, the researchers used the technique of Raman spectroscopy. This technique provided them with strong evidence that the states were the appropriate ones by showing them the chemical bonds in each stage of the reaction. Once they had identified the right states, they studied the sample with synchrotron X-rays. “We expect this new methodology to be of use for many researchers in the field”, Bourgeois explains.

Filming certain proteins while reactions occur has been possible at the European Synchrotron Radiation Facility for some years. However, until today, experiments were restricted to proteins that can be excited by light and are very resistant in crystalline form.

Reference: Katona et al., "Raman-Assisted Crystallography Reveals End-On Peroxide Intermediates in a Nonheme Iron Enzyme", Science, 20 April 2007.

Source: European Synchrotron Radiation Facility

Explore further: Insights into genomic instability during the early stages of embryonic cell development

Related Stories

Toxin from salmonid fish has potential to treat cancer

July 24, 2015

Pathogenic bacteria develop killer machines that work very specifically and highly efficiently. Scientists from the University of Freiburg have solved the molecular mechanism of a fish toxin that could be used in the future ...

The light of fireflies for medical diagnostics

July 22, 2015

In biology and medicine, we often need to detect biological molecules. For example, in cancer diagnostics, doctors need quick and reliable ways of knowing if tumor cells are present in the patient's body. Although such detection ...

'Invisible' protein structure explains the power of enzymes

July 3, 2015

A research group at Umeå University in Sweden has managed to capture and describe a protein structure that, until now, has been impossible to study. The discovery lays the base for developing designed enzymes as catalysts ...

Team shows a protein modification determines enzyme's fate

July 15, 2015

The human genome encodes roughly 20,000 genes, only a few thousand more than fruit flies. The complexity of the human body, therefore, comes from far more than just the sequence of nucleotides that comprise our DNA, it arises ...

RNA insecticide could target specific pests

July 21, 2015

A novel insecticide targets a specific gene in a pest, killing only that bug species on crops and avoiding collateral damage to beneficial insects caused by today's pesticides.

Recommended for you

Short wavelength plasmons observed in nanotubes

July 28, 2015

The term "plasmons" might sound like something from the soon-to-be-released new Star Wars movie, but the effects of plasmons have been known about for centuries. Plasmons are collective oscillations of conduction electrons ...

'Expansion entropy': A new litmus test for chaos?

July 28, 2015

Can the flap of a butterfly's wings in Brazil set off a tornado in Texas? This intriguing hypothetical scenario, commonly called "the butterfly effect," has come to embody the popular conception of a chaotic system, in which ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.