posted on 2021-10-18, 20:45authored byNannan Zhao, Jie Song, Hao Zhang, Ying Lin, Shuangyan Han, Yuanyuan Huang, Suiping Zheng
Diamines
serve as major platform chemicals that can be employed
to a variety of industrial scenarios, particularly as monomers for
polymer synthesis. High-throughput sensors for diamine biosynthesis
can greatly improve the biological production of diamines. Here, we
identified and characterized a transcription factor-driven biosensor
for putrescine and cadaverine in Corynebacterium glutamicum. The transcriptional TetR-family regulatory protein CgmR (CGL2612)
is used for the specific detection of diamine compounds. This study
also improved the dynamic range and the sensitivity to putrescine
by systematically optimizing genetic components of pSenPut. By a single
cell-based screening strategy for a library of CgmR with random mutations,
this study obtained the most sensitive variant CgmRI152T, which possessed an experimentally determined limit of detection
(LoD) of ≤0.2 mM, a K of 11.4 mM, and a utility of 720. Using
this highly sensitive putrescine biosensor pSenPutI152T, we demonstrated that CgmRI152T can be used as a sensor
to detect putrescine produced biologically in a C.
glutamicum system. This high sensitivity and the range
of CgmR will be an influential tool for rewiring metabolic circuits
and facilitating the directed evolution of recombinant strains toward
the biological synthesis of diamine compounds.