PURE system technology is a reconstituted cell-free protein synthesis system invented by Professor Takuya Ueda in the University of Tokyo. (Ref.1, 2)
This system consists of factors for transcription, translation, aminoacylation, and energy regeneration. All proteinous factors and ribosome are highly purified individually and are assembled with substrates, such as amino acids, NTPs, and tRNAs in the buffer. The overview of the system is described in Fig.1. Translational factors include followings; IF1/IF2/IF3 as initiation factors, EF-Tu/EF-Ts/EF-G as elongation factors, RF1/RF2/RF3 as release factors, ribosome recycling factor (RRF), 20 kinds of aminoacyl-tRNA synthetase (ARS), methionyl-tRNA transformylase.
As described above, the PURE system is a reaction system consisting of transcription and translation system only, not like other cell-free protein synthesis system using cell lysates. It indicates that the PURE system has no unknown protein, and its composition can be adjusted as you like.