Expression, Purification And Crystal Growth Of AtCBL9from Arabidopsis Thaliana

AtCBL9which plays an important role in CBL-CIPK system is one of the CBL family members. AtCBL9involves in the regulation of ABA-dependent low K+stress reaction, and interacts with CIPK23. The CBL9-CIPK23complex regulates the ABA-dependent signal transmission and stomatal closure in the condition, of dehydration. The analysis of AtCBL9crystal structure has been the key point in the identification of its function. So far, the structure of AtCBL9protein has not been reported. Our research constructed AtCBL9into the expression vector pET-22b (+), overexpressed in the E. coli, and then protein has been purified through two steps chromatography. SDS-PAGE and DLS analysis shows that AtCBL9protein mainly exists as monomer and dimmer in vitro, the monomer and dimmer are the same protein, and AtCBL9has high degree of purity. Finally microcrystal was selected from monomer protein. These works provide the first step for its structure determination, or rather, its function illumination from molecular level.