IscB
In this study, the micro-base editing system developed based on the gRNA-guided endonuclease IscB was optimized, and targeted evolution techniques such as rational design and random mutation were used to screen protein variants that can improve the activity of the IscB endonuclease and high-activity gRNA variants, and finally a micro-base editing system with high editing activity was obtained. On this basis, the system was modified to develop an efficient micro-two-base editing system, the size of which is in the range of AAV delivery, and also proved its potential to correct disease sites, providing a new tool for gene editing.