| 内容提要: |
In this group meeting,my supervisor invite his friends Joris Beld to join our group meeting. I introduce my project, the content is following:
In Bacillus subtilis, the 60-subunit dodecahedral capsid formed by lumazine synthase (BsLS) acts as a container for trimeric riboflavin synthase (BsRS). To test whether the C-terminal sequence of BsRS is responsible for its encapsulation by BsLS, the green fluorescent protein (GFP) was fused to either the last 11 or last 32 amino acids of BsRS, offering variants GFP11 and GFP32, respectively. After purification, BsLS capsids that had been co-produced in bacteria with GFP11 or GFP32 are 15-fold and 6-fold more fluorescent, respectively, than BsLS co-produced with GFP lacking any BsRS fragment, indicating complex formation. ELISA experiments confirm that GFP11 is localized within the BsLS capsid. In addition, fusing the last 11 amino acids of BsRS to the C-terminus of the Abrin A chain also led to its encapsulation by BsLS at a level similar to that of GFP11. Together, these results demonstrate that the C-terminal tail of BsRS can act as an encapsulation tag capable of targeting other proteins to the BsLS capsid interior. As with the natural BsLS+BsRS complex, mild changes in pH and buffer identity trigger dissociation of the GFP11 guest, accompanied by a substantial expansion of the BsLS capsid. This system for protein encapsulation and release provides a novel tool for bionanotechnology. |