Researchers discover principle for controlling cholera toxin expression through protein binding structure analysis

Identification of the principle of inhibition of fructose transport protein expression related to toxin expression

[에너지데일리 윤호철 기자] A research team in Korea has analyzed the binding structure between proteins related to the expression of cholera toxin for the first time in the world and identified the principle that can control pathogenicity. It is expected to contribute to the control of toxicity of cholera bacteria and the development of therapeutic agents in the future.

The Korea Atomic Energy Research Institute (President Joo Han-kyu) and Advanced Radiation Research Institute (Director Jeong Byeong-yeop) announced on the 20th that Dr. Kim Min-kyu’s research team in the Accelerated Mobility Research Laboratory had found a principle that suppresses the protein related to cholera toxin expression. This is the result of a joint research with Seoul National University Professor Seok Seong-jae’s team.

When infected with Vibrio, a high-risk pathogen that causes cholera or sepsis, the protein transporting fructose is greatly increased. Through this, the relationship between fructose transport protein and toxin production was known, but it was not known how to control the amount of the protein.

In order to find the principle of suppressing fructose transport protein expression, the research team analyzed proteins involved in sugar metabolism regulation, HPr (Histidine-containing Phosphocarrier Protein) and FruR (Fructose Regulator, fructose transport protein activator). ) was noted. Changes in HPr and FruR phenomena were observed when glucose or fructose were present in the environment around cholera bacteria.

Cholera is known to prefer glucose to fructose. In the presence of glucose, HPr and FruR bind and the fructose transport protein is not expressed. The same was true when glucose and fructose were present together. On the other hand, when fructose was present, HPr and FruR were separated and the fructose transport protein was expressed. The joint research team succeeded in confirming this phenomenon for the first time in the world and identifying its molecular mechanism.

In particular, the research team first discovered the bonding method of HPr and FruR using X-ray crystallography. X-ray crystallography is a method of determining the atomic structure by analyzing the diffraction phenomenon that occurs when X-rays, a type of radiation, are applied to atoms. The three-dimensional structure of a protein can be clearly identified. Through this, the binding method between the two proteins and the structural features of the complex, which are distinguished from other bacteria, were confirmed.

Through this study, it was possible to identify the mechanism of gene transcription regulation in bacteria according to external nutrients such as glucose and fructose. This is expected to be used in studies that can control the pathogenicity of Vibrio bacteria through nutrient control in the future.

This achievement was published online on March 29 in Nucleic Acids Research (IF 19.16, top 2.5% in JCR biochemistry and molecular biology), an international journal published by Oxford University in England.

“We have identified a phenomenon that can control the toxicity of bacillus cholera using X-rays,” said Jeong Byeong-yeop, director of the Korea Atomic Energy Research Institute’s Advanced Radiation Research Institute. said.

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