pLysS and pLysE are 4886bp plasmids constructed by insertion of the T7 lysozyme gene into the BamH I site of pACYC184 (1). These plasmids are not cloning vectors; they are used in λDE3 lysogenic hosts to suppress basal expression from the T7 promoter by producing T7 lysozyme, a natural inhibitor of T7 RNA polymerase. The two plasmids differ only by the orientation of the T7 lysozyme gene. In pLysS the T7 lysozyme coding sequence is in the antisense orientation relative to the tet promoter, so only a small amount of T7 lysozyme is produced. In pLysE large amounts of T7 lysozyme are produced from the tet promoter. The construct also contains the weak T7 φ3.8 promoter immediately following the lysozyme gene. The p15A origin of replication is compatible with those found in pBR322- and pUC-derived plasmids. This product is covered under license from Brookhaven National Labs. Commercial entities need to obtain a research use license prior to purchase. Please contact your licensing department to confirm that your company already holds a research use license.，官网链接：https://www.sigmaaldrich.cn/product/mm/69659 默克 科研、开发、生产。 作为生命科学行业的全球领先供应商，我们致力于为科研、生物技术开发和生产，以及制药药物疗法开发和生产提供各类解决方案和服务。

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