The signaling mechanism of bacteria

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Researchers from Russia, Germany, and France have investigated the chemical signaling mechanism inside a bacterial cell. This statement was made by the Moscow Institute of Physics and Technology press-service on May 22, 2017. The scientists hope that this research will help to learn how to weaken or neutralize harmful effects of disease-producing germs, and, in particular, how to develop drugs, to which they wouldn't be resistant. The results of the investigation were published in the Science Journal.

After bacteria get into an organism, for some time they breed without causing a response of the immune system. After exceeding a certain critical number of bacteria, special substances, autoinductors, are secreted into the medium. It is a signal to form a colony. Bacteria usually receive them through two-component signaling systems. Such a system consists of two proteins, namely kinase that receives a signal from the outside of the cell and transmits it inside the cell and regulator that receives the signal inside the cell and activates further reactions.

The authors of the investigation obtained the structure of kinase NarQ from Escherichia coli in two states, inactive, in which the protein doesn't transmit any signal, and active (signaling), in which the transformed protein is connected to a signal substance outside of the cell, and thus transmits the signal into the bacteria. By using the crystallography method, the scientists obtained diffraction patterns of protein molecules ordered in crystal lattice and compared active and inactive forms of the protein.

The researchers also found out that only extracelluar part of the protein changes. That means that the signaling mechanism is universal, and in order to make a receptor define other chemical substances it is enough to change only the extracelluar part, but not the whole mechanism.

The obtained results could be used in creation of substitutes of modern antibiotics, drugs that affect the ability of bacteria to receive signals. Such drugs don't kill the bacteria, but make them harmless to organism. They don't affect the vital functions of microorganisms, and that is why, in contrast to classic antibiotics, bacteria don't develop the resistance to them.


Related information:
Moscow Institute of Physics and Technology (https://mipt.ru/) is a leading Russian university which prepares specialists in theoretical and applied physics, applied mathematics, and related disciplines.

Sources:
https://mipt.ru/news/raskryt_mekhanizm_obonyaniya_u_bakteriy
http://science.sciencemag.org/content/early/2017/05/17/science.aah6345
http://tass.ru/nauka/4265668
https://www.popmech.ru/science/news-364832-raskryt-mehanizm-obonyaniya-u-bakteriy/

Last Modified: 2017/09/05