An efficient expression-secretion system for heterologous protein production in food-grade hosts, Lactobacillus plantarum and Bacillus subtilis, is still required to broaden their applications. The optimal signal peptide compatible with both the desired protein and the target host is important for the system. Here, we constructed new expression-secretion vectors to be used in both bacteria. A natural plasmid originating from food-grade L. plantarum BCC9546 was used as a core vector combined with a strong constitutive promoter, L-ldh promoter, and various signal peptides from several types of L. plantarum proteins: ABC transporter, cell wall-associated and extracellular proteins. A gene encoding 88-kDa amylase isolated from starch-related L. plantarum TBRC470 was used as a gene model to evaluate the systems. By comparing the amounts of secreted amylase from the recombinant strains to that of wild type, all signal peptides gave higher yields of secreted amylase in recombinant B. subtilis. Interestingly, two ABC transporter signal peptides from glutamine and mannose ABC transporters provided noticeably high levels of secreted amylase in recombinant L. plantarum. Moreover, these signal peptides also gave high yields of secreted amylase in recombinant B. subtilis. From the results, the signal peptide of glutamine ABC transporter, which functions in essential amino acid transportation that is a precursor for synthesis of nitrogen-containing compounds and nitrogen homeostasis, has a potential use in development of an efficient expression-secretion system for heterologous protein production in both food-grade hosts.

中文翻译：

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一种有效的 ABC 转运蛋白信号肽指导食品级宿主中的异源蛋白质分泌

在食品级宿主、植物乳杆菌和枯草芽孢杆菌中生产异源蛋白质的有效表达-分泌系统仍然需要扩大其应用范围。与所需蛋白质和目标宿主兼容的最佳信号肽对系统很重要。在这里，我们构建了用于两种细菌的​​新表达分泌载体。源自食品级植物乳杆菌 BCC9546 的天然质粒用作核心载体，结合强组成型启动子、L-ldh 启动子和来自多种植物乳杆菌蛋白的各种信号肽：ABC 转运蛋白、细胞壁相关蛋白和细胞外蛋白。从淀粉相关的植物乳杆菌 TBRC470 中分离出的编码 88-kDa 淀粉酶的基因被用作评估系统的基因模型。通过比较重组菌株与野生型分泌淀粉酶的量，所有信号肽在重组枯草芽孢杆菌中产生更高的分泌淀粉酶产量。有趣的是，来自谷氨酰胺和甘露糖 ABC 转运蛋白的两种 ABC 转运蛋白信号肽在重组植物乳杆菌中提供了显着高水平的分泌淀粉酶。此外，这些信号肽还在重组枯草芽孢杆菌中产生高产量的分泌淀粉酶。从结果来看，谷氨酰胺 ABC 转运蛋白的信号肽，在必需氨基酸转运中起作用，是合成含氮化合物和氮稳态的前体，在开发高效的异源蛋白表达分泌系统方面具有潜在用途在两种食品级宿主中生产。