为了筛选得到利于浸麻类芽孢杆菌Paenibacillus macerans α-环糊精葡萄糖基转移酶(α-CGT酶)分泌表达的信号肽,提高α-CGT酶的分泌表达量,本研究考察了大肠杆菌中外源蛋白分泌表达常用的OmpA、PelB、OmpT和Endoxylanase四个信号肽对重组α-CGT酶在大肠杆菌中胞外表达的影响.在相同的发酵条件下,OmpA信号肽介导的分泌效果最好,发酵72 h,胞外酶活达到了32 U/mL,分别是PelB、OmpT介导效率的2.4倍和4.3倍.Endoxylanase信号肽介导的分泌效果相对较差,在胞外只能检测到很低的α-CGT酶活性,大量α-CGT酶以不可溶性的包涵体形式存在.OmpA信号肽能够有效地介导Paenibacillus macerans α-CGT酶在重组大肠杆菌中的分泌表达.%In order to enhance the secretion efficiency of Paenibacillus macerans α-cycjodextcin glycosy ltransfer:ase (α-CG Tase) in recom binant Escherichia coli, signal peptide opttim ization was carried out ih this study . Signal peptides incjuding 0m pA , PeB , 0m pT and Endoxylanase were obtamed by routine PCR and successive PCR , respectively . Each signal peptide was fused to the N -term inalof them atucre α-C G T ase and expressed in E . coliBL21 (D E3 ) . The α-C G Tase secretion efficiency mediated by different signal peptide was investigated . The results showed that 0m pA was the optimal signal peptide among all. the signal peptides under the same culture conditions . After 72 h of cultivation , the extracellullar α-C G Tase activity could reach 32 U /mL , which was 2 .4-fold and 4 .3-fold that of the PeB and 0m pT signal peptide ,respectively . However, the secretion efficiency of Endoxylanase was the lowest , the detectable α-C G T ase activity was quite low and a large am ount of α-C G T ase existed in the form of inclusion bodies . 0 m pA signal peptide could effectively mediate secretory expression of P . macerans a-C G T ase in recom binant E . coli.
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