How bacteria change movement direction in response to oxygen: Molecular interactions unravelled

June 25, 2012

How single cell organisms like bacteria manage to react to their environment is not yet completely understood. Together with colleagues from Japan, Dr. Samir El-Mashtoly from the RUB Department of Biophysics, led by Prof. Dr. Klaus Gerwert, has gained new insights into the molecular interactions during aerotaxis of Bacillus subtilis, i.e., the dependence of the movement direction on the oxygen concentration in the environment. The research team investigated the conformational changes within the protein HemAT. Via a signal transduction chain, this protein sends a command to the flagellar motor which controls the movement direction. They report in the Journal of Biological Chemistry.

Signal transduction chain

The signal transduction chain starts with binding of oxygen to HemAT's heme domain, which is also known from haemoglobin in the and is called the sensor domain of HemAT. Oxygen binding leads to a conformational change in the sensor domain. This in turn provokes several further conformational changes within HemAT that finally affect the signalling domain of the protein. The signalling domain then transmits the information about a rise in to other proteins within the cell. These proteins forward the message to the motor of the flagellum. The research team investigated how the information travels from the sensor domain of HemAT to its signalling domain.

Protein helices forward the information

For that purpose, Dr. El-Mashtoly used the time-resolved ultraviolet resonance Raman spectroscopic facilities in the Picobiology Institute in Japan. This method provides, for instance, structural information about the conformation of the protein and hydrogen bonding interactions on a nanosecond to microsecond time scale. The results suggest that the conformational change in the sensor domain, i.e., the heme structure, induces the displacement of two protein helices within HemAT. This displacement affects another helix which is continuous with the structure of the signalling domain. Due to a series of conformational changes, the information about oxygen binding thus reaches the signalling domain of the protein.

Explore further: 74,000 .eu domain names suspended

More information: Journal of Biological Chemistry, doi: 10.1074/jbc.M112.357855

Related Stories

74,000 .eu domain names suspended

July 24, 2006

At least 74,000 domain names ending with .eu have been suspended for abusive behavior by a group that controls the name.

Chemists get grip on slippery lipids

August 30, 2007

The ability of the body's cells to correctly receive and convey signals is crucial to good health. Lipids, or fats, play a critical role in this regulation by providing spaces for proteins to gather and network. They are ...

Newly solved structure reveals how cells resist oxygen damage

October 15, 2007

The sun’s rays give life, but also take it away. Singlet oxygen, a byproduct of the photosynthetic process by which certain cells convert sunlight into energy, is a highly toxic and reactive substance that tears cells apart. ...

A tricky tumor virus

January 17, 2008

Epstein-Barr virus (EBV) is a human-pathogenic virus which belongs to the herpes virus family. Almost every adult carries EBV inside. With an infestation rate of more than 90 %, EBV is one of the most successful human viruses. ...

Recommended for you

New insights into the production of antibiotics by bacteria

July 31, 2015

Bacteria use antibiotics as a weapon and even produce more antibiotics if there are competing strains nearby. This is a fundamental insight that can help find new antibiotics. Leiden scientists Daniel Rozen and Gilles van ...

Out of the lamplight

July 31, 2015

The human body is governed by complex biochemical circuits. Chemical inputs spur chain reactions that generate new outputs. Understanding how these circuits work—how their components interact to enable life—is critical ...

Cell aging slowed by putting brakes on noisy transcription

July 30, 2015

Working with yeast and worms, researchers found that incorrect gene expression is a hallmark of aged cells and that reducing such "noise" extends lifespan in these organisms. The team published their findings this month in ...

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.