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OKAYAMA, Japan, March 18, 2019 / PRNewswire / – In a recent study published in Protein and Proteomics Researchers at Okayama University, show how bacteria attach to organisms before they infect them.
Bacteria have been invading animals and plants for a long time. One of their most complex but least understood mechanisms is their ability to adhere to other organisms. A research team led by a professor Takashi Tamura at Okayama University unveiled the role of a molecule, DsbA, and how its chemical properties control this adherent function of bacteria.
Professor Tamura has already shown that before bacteria can adhere to other living things, certain structures on the surface of the bacteria must be stabilized to form a solid scaffold. Special proteins present in the bacteria are responsible for this stabilization. To better understand this process, Professor Takashi Tamura The team used a virus that only attacks bacteria (bacteriophage). This virus binds to an appendage-like structure found on the bacterial surface. DsbA is the protein responsible for the stabilization of this appendix to facilitate this fixation. To decipher the work of DsbA, the team created several mutants of bacteria, each with a different form of DsbA protein. The code responsible for giving DsbA a chemical charge was different in each mutant. A bacteriophage called M13 was then introduced into these bacteria, grown on a plate.
Ideally, when M13 attaches and successfully infects bacteria, "plaques" of viral colonies will be observed on the plate, instead of bacterial colonies. These plaques were measured for all different mutants. It has been found that a particular mutant (DsbA [CDIC]) had 40 times more plaque than any other mutant or non-mutated bacterium. The charge of this mutant was much lower than that of the unmutated protein. However, another mutant, also with a low charge, had no more plaques. This suggests that the mutated code of (DsbA [CDIC]) could have additional effects. Using structural mapping, the team then discovered that DsbA [CDIC] had enlarged connecting pockets, compared to other variants. This could facilitate a better connection of the scaffolding appendix.
An overview of these mechanisms of attachment can help develop strategies for fighting bacteria. Antibiotic resistance is also transmitted from one bacterium to another by close contact. Designing drugs that could inactivate DsbA function factors seems to be one of these strategies.
Context
Proteins and structure: Proteins that bind to other proteins and modulate their activity are called enzymes. Special regions on these proteins called active sites are responsible for this function. The active site consists of a "binding site", a pocket in which the partner protein actually binds and a "catalytic site" that gives the protein a chemical charge. This charge provides the necessary energy for the protein to undergo a chemical reaction. In the case of DsbA, the codes on the catalytic site have been modified to create the mutants.
bacteriophage: Bacteriophages or "bacteria eaters" are viruses that attack and then hijack bacteria. The first step in this process requires the bacteriophage to attach to the bacterial surface. In general, the bacteriophage binds to the F-pilus, an appendage-like structure on the surface of the bacterium.
Reference
Shinya Sutoh, Yuko Uemura, Yuko YamaguchiAsako Kiyotou Rena SugiharaMakiko Nagayasu, Mihoko KurokawaKoreaki Ito, Naoki Tsunekawa, Michiko Nemoto, Kenji Inagaki, Takashi Tamura. The redox setting of the oxidizing disulfide oxidoreductase generates a potent disulfide isomerase. Biochimica and Biophysica Acta – Proteins and Proteomics, 1867 (2019), 194-201.
DOI: doi.org/10.1016/j.bbapap.2018.12.005
OUpdated Medical Research of Kayama University (OR-MRU)
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About the University of Okayama
The University of Okayama is one of the largest comprehensive universities in Japan with roots going back to the medical training center sponsored by the lord of Okayama and created in 1870. The University, which now has 1,300 professors and 13,000 students, offers courses in specialties ranging from medicine in pharmacy, human sciences and physical sciences.
Okayama University is located in the heart of Japan about 3 hours west of Tokyo by Shinkansen.
Website: http://www.okayama-u.ac.jp/index_e.html
Correspondence to
Professor Takashi Tamura, Ph.D.
Department of Bioresource Chemistry,
Okayama University Graduate School of Environmental
and life sciences, 1-1-1, Tsushima-naka, Kita-ku, Okayama
700-8530, Japan.
E-mail: [email protected]
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1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
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