The Transport Mechanism Of Phenylpropanoids In Escherichia Coli BL21by Proteomics

Phenylpropanoids are polyphenolic compounds which are existed in plants in lowamount. Distinct in their constructs, Phenylpropanoids are particularly biologically active inanti-oxidant, anti-bacterial, anti-viral, anti-tumor, anti-allergic, anti-obesity, regulation ofthe immune, cardiovascular, endocrine and etc, so that they have broad application inmedicine and food. Because of their complex structures, it is difficult to synthesize thesecompounds by chemical method. Using microbial to synthesize these compounds hasattracted more and more peoples’ attention due to many advantages. But there are also somebottlenecks in this method, one of which is still not very clear transport mechanism aboutthese compounds in microbial. Transport of phenylpropanoid out of microorganism istherefore essential for improving production.Escherichia coli were often used as phenylpropanoids production host strain. In thisstudy, E. coli BL21(DE3) was the object strain, explored the membrane protein whichrelated to phenylpropanoids transport or tolerance, and validated the result by molecularbiology.In this study,16membrane proteins were differentially expressed in E. coli in responseto three typical phenylpropanoids (resveratrol, naringenin and rutin) were identified using aproteomics approach. OmpA, OmpF, OmpW, FadL, OppD, PotG, AtpD and AtpH wereup-regulated2-fold or more and TolC, LamB, MalK, MalE, ManX, YaeT, YgaU and OppAwere down-regulated2-fold or more. These proteins were located in the membrane andinteracted each other. In order to verify the correctness of proteomics result, these proteins(except of AtpD and AtpH) were verified by qPCR. The result was in accordance with theproteomic data exception of TolC, suggesting this protein could be regulated at thetranslational level.The function of these proteins was determined using gene overexpression and silencing.Overexpression of ompA, fadL and gene silencing of lamB, malE, malK, ygaU and manXsignificantly increased cell growth in the presence of the phenylpropanoids. The resultsuggested OmpA and FadL might play important roles in the transmembrane transportationof phenylpropanoids in E. coli. LamB, MalE, MalK and ManX might participate inphenylpropanoid uptake. The role of YgaU enhancing the tolerance of phenylpropanoidsremained to be determined. These results might assist the engineering of microbes withenhanced phenylpropanoid producing capabilities.