A joint research team from Chiba University Graduate School, Kanagawa Institute of Technology, and Waseda University introduced cysteine ​​into a protein that controls the transcription of microbial DNA, converting a protein that normally does not react to arsenic into a protein that responds to arsenic. Successful. Arsenic can now be detected using inexpensive analytical equipment.

 Arsenic is a highly toxic element that exists everywhere on earth, and long-term ingestion of even small amounts can cause health problems such as skin diseases, neurological disorders, and cancer, so monitoring and detecting arsenic in the environment is important. Chemical analysis using expensive equipment was common for detecting arsenic contamination, but equipment costs were high and analysis required expertise.

 The research team focused on the fact that arsenic-binding proteins in microorganisms' bodies respond by binding arsenic to three cysteines. Even a protein that is originally unresponsive to arsenic will become responsive to arsenic by introducing three cysteines, and if that protein is further introduced into E. coli, any protein, not just conventional arsenic-binding proteins, can be used as a microbial arsenic sensor. I thought it might be possible.

 Therefore, we created a mutant (BetI3cys) in which three positions in BetI, a cysteine-free E. coli choline-responsive transcriptional repressor, were replaced with cysteine. When this was introduced into E. coli and exposed to arsenic, the bacteria responded 3% more highly than in the absence of arsenic, but had no response to copper or zinc. This led to the creation of a sensor protein with high specificity for arsenic.

 Based on this result, it is expected that by introducing cysteine, various proteins can be modified into arsenic sensors that detect arsenic pollution in the environment. This will enable facilities without advanced equipment to detect the presence of arsenic using inexpensive analytical equipment.

Paper information:【ACS Omega】Imparting As(III) responsiveness to the choline response transcriptional regulator BetI

Waseda University

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Waseda University has created an unparalleled environment in which all students can hone their ability to take on unanswered issues based on the three founding principles of "independence of academics, utilization of academics, and creation of model people."Aiming to be a world-class university with unwavering international competitiveness, "WASEDA that shines in the world," "Waseda for research" and "[…] for education.

Chiba University

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Chiba University has 10 faculties, 7 graduate schools / faculties, and a large number of affiliated facilities, and has specialized knowledge and skills, high problem-solving ability, high intelligence, ethical standards, and rich humanity, and has an interdisciplinary perspective. We aim to develop human resources who can play an active role internationally.Actively promote the enhancement of liberal arts education and the internationalization of educational activities, which are the basis of this […]

Kanagawa Institute of Technology

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