Transglutaminase (TGase) induces the cross-linking of proteins by catalyzing an acyl transfer reaction. TGase is a zymogen, activated by the removal of its pro-region. Because the pro-region is crucial for folding and inhibition of the TGase activity, the recombinant expression of the mature TGase (mTGase) without the pro-region, usually results in inactive inclusion bodies or low protein yield. Here, Streptomyces netropsis TGase was fused with Escherichia coli lysyl-tRNA synthetase (LysRS), as a module with chaperoning activity in an RNA dependent manner (chaperna). The TGase activity from purified fusion protein induced via the removal of LysRS by tev protease in vitro. Moreover, active mTGase was produced in E. coli via an intracellular cleavage system, wherein LysRS-mTGase was cleaved by the coexpressed tev protease in vivo. The results suggest that LysRS essentially mimics pro-region, which exerts a dual function—folding of TGase into active conformation and keeping it as dormant state—in an RNA-dependent manner. Thus, trans-acting RNAs, prompt the cis-acting chaperone function of LysRS, while being mechanistically similar to the intramolecular chaperone function of the pro-region. These results could be implemented and extended for the folding of “difficult-to-express” recombinant proteins, by harnessing the chaperna function.
Bibliographical noteFunding Information:
This study was supported by grants from the Ministry of Agriculture, Food and Rural Affairs of the Korean Government (716002‐7 and 315044031SB010) and the National Research Foundation of Korea (2014M3A9E4064743 and 2018M3A9H4079358).
Ministry of Agriculture, Food and Rural Affairs of the Korean Government, Grant/Award Numbers: 716002‐7, 315044031SB010; National Research Foundation of Korea, Grant/Award Numbers: 2014M3A9E4064743, 2018M3A9H4079358
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All Science Journal Classification (ASJC) codes
- Applied Microbiology and Biotechnology