Abstract: Labeling or modifying the target protein in vivo or vitro is one of the important methods to study the protein structure and function， but there are many shortcomings in current modifying methods, especially they may have the negative effect on the structure and function of the protein. To avoiding or reducing these disadvantages, modification by trans-split intein is one effective method. However, the application of the technique is limited because the nature split intein rarely exists. In this paper, two split inteins in vivo with fewer cysteines and S1-split intein in vitro with high split efficient were obtained by Inbase selection, site-directed mutations, Western Blot and other techniques. So the research supplies a reliable biology tool for controllable and specific N-terminal labeling and application of the target proteins.

Key words: N-terminal cysteine free split intein, protein N-terminal labeling, protein splicing