Defect of RNA pyrophosphohydrolase RppH enhances fermentative production of L-cysteine in <i>Escherichia coli</i>
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- Morigasaki Susumu
- Graduate School of Life and Environmental Sciences, University of Tsukuba
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- Umeyama Akinori
- Research & Development Center, Carlit Holdings Co., Ltd.
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- Kawano Yusuke
- Graduate School of Life and Environmental Sciences, University of Tsukuba
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- Aizawa Yasushi
- Research & Development Center, Carlit Holdings Co., Ltd.
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- Ohtsu Iwao
- Graduate School of Life and Environmental Sciences, University of Tsukuba
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<p>Fermentative production of L-cysteine has been established using Escherichia coli. In that procedure, thiosulfate is a beneficial sulfur source, whereas repressing sulfate utilization. We first found that thiosulfate decreased transcript levels of genes related to sulfur assimilation, particularly whose expression is controlled by the transcription factor CysB. Therefore, a novel approach, i.e. increment of expression of genes involved in sulfur-assimilation, was attempted for further improvement of L-cysteine overproduction. Disruption of the rppH gene significantly augmented transcript levels of the cysD, cysJ, cysM and yeeE genes (≥1.5-times) in medium containing sulfate as a sole sulfur source, probably because the rppH gene encodes mRNA pyrophosphohydrolase that triggers degradation of certain mRNAs. In addition, the ΔrppH strain appeared to preferentially uptake thiosulfate rather than sulfate, though thiosulfate dramatically reduced expression of the known sulfate/thiosulfate transporter complexes in both ΔrppH and wild-type cells. We also found that both YeeE and YeeD are required for the strain without the transporters to grow in the presence of thiosulfate as a sole sulfur source. Therefore, yeeE and yeeD are assigned as genes responsible for thiosulfate uptake (tsuA and tsuB, respectively). In final, we applied the ΔrppH strain to the fermentative production of L-cysteine. Disruption of the rppH gene enhanced L-cysteine biosynthesis, as a result, a strain producing approximately twice as much L-cysteine as the control strain was obtained.</p>
収録刊行物
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- The Journal of General and Applied Microbiology
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The Journal of General and Applied Microbiology 66 (6), 307-314, 2020
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
