title: Identification of membrane proteins associated with phenylpropanoid tolerance and transport in Escherichia coli BL21.
abstract: Phenylpropanoids are phytochemicals produced by some plants and possess a wide variety of biological activities. These compounds exist in plants in low amounts. Production of them in genetically engineered microorganisms has many advantages. A majority of functional phenylpropanoids are toxic to microbial hosts. Export of these compounds may relieve the cellular toxicity and increase the yield. However, proteins and mechanisms involved in phenylpropanoids transport and tolerance remain poorly understood. In this study, 16 membrane proteins that were differentially expressed in Escherichia coli in response to three typical phenylpropanoids (resveratrol, naringenin and rutin) were identified using a membrane proteomics approach. These proteins included outer membrane proteins OmpA, OmpF, OmpW, FadL, TolC, LamB, and YaeT, peripheral membrane proteins AtpD, AtpH, YgaU, OppA, MalK, and MalE, and cytoplasmic membrane proteins OppD, PotG, and ManX. Functions of these proteins were determined by using gene overexpression and silencing. The results suggest that OmpA and FadL may play important roles in the transmembrane export of phenylpropanoids in E. coli. LamB, MalE, MalK and ManX may participate in phenylpropanoid uptake. The role of YgaU in enhancing the tolerance to phenylpropanoids remains to be determined. These results may assist the engineering of microorganisms with enhanced phenylpropanoid producing capabilities.
  
  
  CONCLUSIONS
  Phenylpropanoids are phytochemicals produced by some plants and possess a wide variety of biological activities. Both the tolerance and the transport of phenylpropanoids play important roles in systematic metabolic engineering of microorganisms to produce these phytochemicals. Both specific and non-specific transporters are essential for these functions but remain poorly understood. This research utilized membrane proteomics to identify E. coli BL21 (DE3) membrane proteins that may be involved in phenylpropanoid transport and tolerance. These results may facilitate the construction of more efficient microbial phenylpropanoid producers through genetic engineering of membrane transporter proteins.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China. Electronic address: zhoujw1982@jiangnan.edu.cn.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Xu
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Peiran
authors.initials: P
authors.lastname: Liu
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China. Electronic address: lijianghua@jiangnan.edu.cn.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D000897:Anti-Ulcer Agents / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D044950:Flavanones / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D010666:Phenylpropionates / Q000494:pharmacology*; D040901:Proteomics; D000077185:Resveratrol; D012431:Rutin / Q000494:pharmacology; D013267:Stilbenes / Q000494:pharmacology
chemical_list: D000897:Anti-Ulcer Agents; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D044950:Flavanones; D008565:Membrane Proteins; D010666:Phenylpropionates; D013267:Stilbenes; D012431:Rutin; C005273:naringenin; D000077185:Resveratrol
keywords: Genomics; Membrane proteomics; Phenylpropanoids; Tolerance; Transport