In our project, we aim to establish a standardized interface for protein modification on silicon dioxide (SiO2) surfaces. To achieve this, we intend to modify the LPG adapter protein. We have chosen a silica-binding peptide for binding to SiO2 and will utilize the avidin-biotin system, a powerful affinity-based coupling system, as the bridge between the interface and the target protein. We chose streptavidin from the avidin family.
1. SBP affinity selection:
We conducted a literature review on the SBP sequence and found that by adding a polyhistidine tag at the C-terminus of SBP, with isoleucine residues interspersed, the polyhistidine side chains will form an imidazole plane that interacts more strongly with silicon dioxide. Among the SBP variants we searched, SBP5 was ultimately selected due to its high affinity and relative stability in the intended environment.
![sorry](https://static.igem.wiki/teams/4623/wiki/engineering/fig1.png)
Figure 1| SBP5 Amino Acid Sequence
2. Transformation of SBP oligomerization:
The affinity of SBP is influenced by steric hindrance between the SBP sequence and the avidin protein. Excessive steric hindrance can greatly reduce the binding strength. To enable the SBP to connect with avidin, it is necessary to introduce a linker sequence between SBP and avidin. In our study, we selected streptavidin, a tetrameric protein with a size of 66 kDa, from the avidin family. We chose a flexible linker sequence (GGGGS)*12 to provide multidirectional extension in space, thereby improving the efficiency of streptavidin and biotin binding.