Tyrosine phosphorylation is a pivotal post-translational modification which regulates enzymatic activity, protein conformation, and protein-protein interactions. Protein tyrosine kinase (PTK) is closely related to the occurrence of diseases and the disorder of its activity is the major cause of many diseases. PTK has become an important target for therapeutic drug design. Currently, therapeutic drug design is mainly based on the recognition of different PTK active states. PTK activity is primarily regulated by the tyrosine phosphorylation of activation loop. Therefore, establishing a new method for detecting the tyrosine phosphorylation of PTK activation loop will provide us insight into the regulatory mechanism of PTK activity and new clue to therapeutic drug design.

Dr. Jiangyun wang’s group at the Institute of Biophysics, CAS recently discovered the highly efficient genetic incorporation of 3,5-difluorotyrosine (F2Y) in E. coli, and demonstrated its utility as a 19F NMR probe for tyrosine phosphorylation. Using 19F NMR spectroscopy, the group provided for the first time direct evidence that the activation loop phosphotyrosine (pTyr574) in the prokaryotic protein tyrosine kinase Etk interacts with Arg614, locking Etk in an active conformation. It also showed that dasatinib (a cancer drug targeting BCR/ABL and Src) binding to Src causes significant conformation changes in its activation loop bearing pTyr416. This sensitive, selective, and robust method may provide a valuable tool for elucidating PTK activation mechanism, and screening for novel inhibitors targeted for specific PTK/substrate protein interactions.

This work was published in an article, entitled “A Genetically Encoded 19F NMR Probe for Tyrosine Phosphorylation” on the Angewandte Chemie International Edition in February 2013. It was supported by grants from the Ministry of Science and Technology of China, the Natural Science Foundation of China and the Chinese Academy of Sciences.

Figure legend: Genetically encoded 19F NMR probe for detecting the conformation change of PTK activation loop.

Article link：http://onlinelibrary.wiley.com/doi/10.1002/anie.201300463/abstract