School of Energy and Chemical Engineering, UNIST, Ulsan, 44919, Republic of Korea.
School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 46241, Republic of Korea.
Sci Rep. 2020 Nov 4;10(1):19064. doi: 10.1038/s41598-020-76120-3.
Previously, we have reported that 3-hydroxypropionate (3-HP) tolerance in Escherichia coli W is improved by deletion of yieP, a less-studied transcription factor. Here, through systems analyses along with physiological and functional studies, we suggest that the yieP deletion improves 3-HP tolerance by upregulation of yohJK, encoding putative 3-HP transporter(s). The tolerance improvement by yieP deletion was highly specific to 3-HP, among various C2-C4 organic acids. Mapping of YieP binding sites (ChIP-exo) coupled with transcriptomic profiling (RNA-seq) advocated seven potential genes/operons for further functional analysis. Among them, the yohJK operon, encoding for novel transmembrane proteins, was the most responsible for the improved 3-HP tolerance; deletion of yohJK reduced 3-HP tolerance regardless of yieP deletion, and their subsequent complementation fully restored the tolerance in both the wild-type and yieP deletion mutant. When determined by 3-HP-responsive biosensor, a drastic reduction of intracellular 3-HP was observed upon yieP deletion or yohJK overexpression, suggesting that yohJK encodes for novel 3-HP exporter(s).
先前，我们曾报道过缺失研究较少的转录因子 yieP 可提高大肠杆菌 W 对 3-羟基丙酸（3-HP）的耐受性。在此，通过系统分析以及生理和功能研究，我们提出 yieP 缺失通过上调编码潜在 3-HP 转运蛋白的 yohJK 来提高 3-HP 耐受性。yieP 缺失引起的耐受性提高对各种 C2-C4 有机酸中的 3-HP 具有高度特异性。ChIP-exo 结合转录组分析（RNA-seq）的 YieP 结合位点作图支持了进一步功能分析的七个潜在基因/操纵子。其中，yohJK 操纵子编码新型跨膜蛋白，是提高 3-HP 耐受性的最主要因素；yohJK 的缺失降低了 3-HP 的耐受性，而无论 yieP 是否缺失，它们的后续互补完全恢复了野生型和 yieP 缺失突变体的耐受性。当通过 3-HP 响应生物传感器测定时，yieP 缺失或 yohJK 过表达时观察到细胞内 3-HP 急剧减少，表明 yohJK 编码新型 3-HP 外排泵。
