Analysis of the Staphylococcus epidermidis genes epiF, -E, and -G involved in epidermin immunity
Analysis of the Staphylococcus epidermidis genes epiF, -E, and -G involved in epidermin immunity
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DOI：
10.1128/jb.178.2.531-536.1996
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发表时间：
1996-01-01
影响因子：
3.2
通讯作者：
Gotz, F
中科院分区：
文献类型：
--
作者：
Peschel, A;Gotz, F
抗生素表皮蛋白由表皮葡萄球菌Tu3298产生。已知的参与表皮蛋白生物合成和调控的基因被组织成操纵子(EPABCD和EPQP)，它们被编码在54kb的pTu32上。在这里，我们描述了位于结构基因EPIA上游的DNA区域的特征，该区域介导免疫和增加表皮蛋白的产生。2.6kbDNA片段的序列显示了3个可能形成操纵子的开放阅读框：Eepf、-E和-G，在克隆宿主肉色葡萄球菌中，这3个基因介导了对表皮蛋白的耐受性增加，其中以S的免疫水平最高，为7倍。第一个基因的启动子EPF对激活蛋白Epiq作出反应，并含有一个回文序列，该序列与EPIA启动子的Epiq结合位点相似，也被Epiq激活。由于EPF、-E或-G的失活导致了免疫表型的完全丧失，突变株Tu3298被含有这三个基因的DNA片段所补充，与含有生物合成基因EPABCDQP的pTepe14一起被克隆后，表皮蛋白的产量大约提高了5倍。EpiF、-E和-G蛋白在推导序列和结构上与各种ABC转运蛋白系统的组成成分相似，EpiF是一种亲水性蛋白，具有保守的ATP结合位点，而EpiF和-G有六个交替的疏水区，很可能构成完整的膜域，当EpiF在肉质链霉菌中大量生产时，它至少部分与细胞膜有关。讨论了EpiFEG介导免疫的一种潜在机制。
The lantibiotic epidermin is produced by Staphylococcus epidermidis Tu3298. The known genes involved in epidermin biosynthesis and regulation are organized as operons (epiABCD and epiQP) that are encoded on the 54-kb plasmid pTu32. Here we describe the characterization of a DNA region that mediates immunity and increased epidermin production, located upstream of the structural gene epiA. The sequence of a 2.6-kb DNA fragment revealed three open reading frames, epiF, -E, and -G, which may form an operon, In the cloning host Staphylococcus carnosus, the three genes mediated an increased tolerance to epidermin, and the highest level of immunity (sevenfold) was achieved with S, carnosus carrying epiFEG and epiQ. The promoter of the first gene, epiF, responded to the activator protein EpiQ and contained a palindromic sequence similar to the EpiQ binding site of the epiA promoter, which is also activated by EpiQ. Inactivation of epiF, -E, or -G resulted in the complete loss of the immunity phenotype, An epidermin-sensitive S. epidermidis Tu3298 mutant was complemented by a DNA fragment containing all three genes, When the epiFEG genes were cloned together with plasmid pTepi14, containing the biosynthetic genes epiABCDQP, the level of epidermin production was approximately fivefold higher. The proteins EpiF, -E, and -G are similar in deduced sequence and proposed structure to the components of various ABC transporter systems, EpiF is a hydrophilic protein with conserved ATP-binding sites, while EpiE and -G have six alternating hydrophobic regions and very likely constitute the integral membrane domains, When EpiF was overproduced in S. carnosus, it was at least partially associated with the cytoplasmic membrane. A potential mechanism for how EpiFEG mediates immunity is discussed.