Structural studies of a new cesium ion scavenger using a toxin having molecular switch ability

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K14048
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Green/Environmental chemistry
• Research Institution: Kyoto Institute of Technology
• Principal Investigator: Kengo Kitadokoro 京都工芸繊維大学, 分子化学系, 准教授 (60283587)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 毒素 / セシウム結合タンパク質 / X線構造解析 / XSAFS

Outline of Final Research Achievements

The effective removal of the radio cesium is the problem that is urgent issues. There is not yet the development example of the remover using the property that protein couples with a cesium ion. The structure of the bacteria toxin (CPE) that an applicant analyzed structure has two metal ions binding sites in the center of the trimer. It was found that there were two glutamate clusters which have negative electric charge gathered in the molecular center of the trimer by 3D structure determination. It was revealed that these clusters have ability of various metal ions binding. It was suggested that this glutamate cluster is available to removing the cesium ion, and in this study, by using quick change methods of PCR, it was succeeded to make various mutant proteins for increasing the cesium binding property, and it was proved that some mutants can bind the cesium ion in this cluster.

Free Research Field

構造生物化学

Academic Significance and Societal Importance of the Research Achievements

データ測定の結果、いずれの変異体CPEにおいても約2.3 Å 分解能の回折データを収集出来た。今回、９種類の変異体帯を作成し、すべての変異体について結晶化を行い、構造決定し、構造精密化を行った。CPE-E94D(不活型含む)及びCPE-D48A-E110D(不活型のみ)については、結晶構造解析ならびにXAFS解析の両方でセシウムの結合を確認できた。XAFS解析の結果、結合している分子がセシウムであると確認できた。また、クラスター部分のアミノ酸が結合する金属イオンが、変異体の種類によって変化する可能性があることが示唆された