School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
Institute of Physical Science and Information Technology, School of Life Sciences, Anhui University, Hefei, 230601, China.
J Ind Microbiol Biotechnol. 2019 Jul;46(7):1013-1024. doi: 10.1007/s10295-019-02178-2. Epub 2019 Apr 23.
In this work, we found that the Lrp/AsnC family protein SACE_5717 negatively regulated erythromycin biosynthesis in S. erythraea. Disruption of SACE_5717 led to a 27% improvement in the yield of erythromycin in S. erythraea A226. SACE_5717 directly repressed its own gene expression, as well as that of the adjacent gene SACE_5716 by binding to the target sequence 5'-GAACGTTCGCCGTCACGCC-3'. The predicted LysE superfamily protein SACE_5716 directly influenced the export of lysine, histidine, threonine and glycine in S. erythraea. Arginine, tyrosine and tryptophan were characterized as the effectors of SACE_5717 by weakening the binding affinity of SACE_5717. In the industrial S. erythraea WB strain, deletion of SACE_5717 (WBΔSACE_5717) increased erythromycin yield by 20%, and by 36% when SACE_5716 was overexpressed in WBΔSACE_5717 (WBΔSACE_5717/5716). In large-scale 5-L fermentation experiment, erythromycin yield in the engineered strain WBΔSACE_5717/5716 reached 4686 mg/L, a 41% enhancement over 3323 mg/L of the parent WB strain.
在这项工作中，我们发现 Lrp/AsnC 家族蛋白 SACE_5717 负调控红色糖多孢菌中红霉素的生物合成。SACE_5717 的敲除导致红霉素在红色糖多孢菌 A226 中的产量提高了 27%。SACE_5717 通过与靶序列 5'-GAACGTTCGCCGTCACGCC-3' 结合，直接抑制自身基因表达以及相邻基因 SACE_5716 的表达。预测的 LysE 超家族蛋白 SACE_5716 直接影响红色糖多孢菌中赖氨酸、组氨酸、苏氨酸和甘氨酸的输出。精氨酸、酪氨酸和色氨酸被鉴定为 SACE_5717 的效应物，通过削弱 SACE_5717 的结合亲和力。在工业生产红色糖多孢菌 WB 菌株中，敲除 SACE_5717（WBΔSACE_5717）使红霉素产量提高了 20%，当 SACE_5716 在 WBΔSACE_5717 中过表达时，红霉素产量提高了 36%（WBΔSACE_5717/5716）。在 5-L 大规模发酵实验中，工程菌株 WBΔSACE_5717/5716 的红霉素产量达到 4686mg/L，比亲本 WB 菌株的 3323mg/L 提高了 41%。
