Phosphorylated and non-phosphorylated HCK kinase domains produced by cell-free protein expression

Publication date: October 2018 Source:Protein Expression and Purification, Volume 150 Author(s): Kazushige Katsura, Yuri Tomabechi, Takayoshi Matsuda, Mayumi Yonemochi, Junko Mikuni, Noboru Ohsawa, Takaho Terada, Shigeyuki Yokoyama, Mutsuko Kukimoto-Niino, Chie Takemoto, Mikako Shirouzu Since phosphorylation is involved in various physiological events, kinases and interacting factors can be potential targets for drug discovery. For the development and improvement of inhibitors from the point of view of mechanistic enzymology, a cell-free protein synthesis system would be advantageous, since it could prepare mutant proteins easily. However, especially in the case of protein kinase, product solubility remains one of the major challenges. To overcome this problem, we prepared a chaperone-supplemented extract from Escherichia coli BL21 cells harboring a plasmid encoding a set of chaperone genes, dnaK, dnaJ, and grpE. We explored cell-disruption procedures and constructed an efficient protein synthesis system. Employing this system, we produced the kinase domain of human hematopoietic cell kinase (HCK) to obtain further structural information about its molecular interaction with one of its inhibitors, previously developed by our group (RK-20449). Lower reaction temperature improved the solubility, and addition of a protein phosphatase (YpoH) facilitated the homogeneous production of the non-phosphorylated kinase domain. Crystals of the purified product were obtained...
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research