| 研究実績の概要 |
The W5052 strain isolated from unusual Tokyo food-poisoning outbreaks did not harbor the cpe nor produce C. perfringens enterotoxin (CPE). On the other hand, they secreted a novel enterotoxin, CPILE. It is consisting of two components: CPILE-a, which acts as an enzymatic ADP-ribosyltransferase and CPILE-b, a membrane binding component.
The enterotoxicity of CPILE relies on endocytosis of the CPILE complex into the cytosol. CPILE-b binds to the specific cell receptor and assists translocation of CPILE-a into the target cell. How CPILE-b binds to the particular cell receptor is still unclear.
The purified CPILE-b was subjected to cleavage pro-sequence region by trypsin to trigger oligomerization. It should be noted that the SDS-PAGE of the purified CPILE-b showed both pro-sequence and CPILE-b bands. Then, the purified CPILE-b was concentrated and crystalized using standard crystallization kits via hanging drop vapor diffusion method. CPILE-b crystals found after one month screening and SDS-PAGE of selected crystals confirmed that they were CPILE-b crystals. However, poor data set was collected and failed to assign the correct space group even though the good shapes of CPILE-b crystals were used. The pro-sequence probably nicked to CPILE-b and disturbed good quality of crystal formation.
In conclusion, N-terminal GST-tag CPILE-b with regular purification procedure failed to separate pro-sequence region from CPILE-b body. The condition that triggers oligomerization of CPILE-b should be further investigation.
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