Yersiniabactin production requires the thioesterase domain of HMWP2 and YbtD, a putative phosphopantetheinylate transferase
Yersiniabactin production requires the thioesterase domain of HMWP2 and YbtD, a putative phosphopantetheinylate transferase
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DOI：
10.1128/iai.70.8.4204-4214.2002
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发表时间：
2002-08-01
影响因子：
3.1
通讯作者：
Perry, RD
中科院分区：
文献类型：
--
作者：
Bobrov, AG;Geoffroy, VA;Perry, RD
鼠疫耶尔森氏菌（鼠疫的病原体）发病的一个必要条件是耶尔森氏菌吸铁蛋白（Ybt）依赖铁转运系统，该系统编码于鼠疫耶尔森氏菌染色体pgm位点内的高致病性岛（HPI）内。HPI中的9个基因产物在Ybt的非核糖体肽合成(NRPS)/聚酮合成（PK）或运输中具有功能。NRPS/PK合成酶或合成酶通常由磷酸腺苷化激活。然而，在pgm基因座内没有发现与已知磷酸蚁基（P-pant）转移酶相似的产物。我们已经发现了一个编码在HPI和pgm位点外的基因ybtD，它是Ybt系统功能所必需的，并且与大肠杆菌的其他p -p转移酶（如EntD）相似。ybtD内的缺失产生了一个产铁载体缺陷的菌株（KIM6-2085+）。该菌株不能在37℃的缺铁培养基上生长，但可以与产ybt的鼠疫菌培养上清液杂交。ybtD的启动子区与lacZ融合；该报告基因的β -半乳糖苷酶表达不受细菌细胞铁状态或YbtA的调节，YbtA是ybt系统中其他基因的正调节因子。ybtD突变体不能表达Ybt指示蛋白（高分子量蛋白1 [HMWP1]、HMWP2和Psn），这种模式与其他几种Ybt生物合成突变体相似。相比之下，在HMWP2末端硫酯酶结构域中含有单个氨基酸取代（S2908A）的细胞没有表现出任何ybt调节缺陷，但在缺铁条件下没有发生细胞外ybt。
One requirement for the pathogenesis of Yersinia pestis, the causative agent of bubonic plague, is the yersiniabactin (Ybt) siderophore-dependent iron transport system that is encoded within a high-pathogenicity island (HPI) within the pgm locus of the Y. pestis chromosome. Nine gene products within the HPI have demonstrated functions in the nonribosomal peptide synthesis (NRPS)/polyketide (PK) synthesis or transport of Ybt. NRPS/PK synthetase or synthase enzymes are generally activated by phosphopantetheinylation. However, no products with similarities to known phosphopantetheinyl (P-pant) transferases were found within the pgm locus. We have identified a gene, ybtD, encoded outside the HPI and pgm locus, that is necessary for function of the Ybt system and has similarities to other P-pant transferases such as EntD of Escherichia coli. A deletion within ybtD yielded a strain (KIM6-2085+) defective in siderophore production. This strain was unable to grow on iron-deficient media at 37degreesC but could be cross-fed by culture supernatants from Ybt-producing strains of Y. pestis. The promoter region of ybtD was fused to lacZ; beta-galactosidase expression from this reporter was not regulated by the iron status of the bacterial cells or by YbtA, a positive regulator of other genes of the ybt system. The ybtD mutant failed to express indicator Ybt proteins (high-molecular-weight protein 1 [HMWP1], HMWP2, and Psn), a pattern similar to those seen with several other ybt biosynthetic mutants. In contrast, cells containing a single amino acid substitution (S2908A) in the terminal thioesterase domain of HMWP2 failed to exhibit any ybt regulatory defects but did not elaborate extracellular Ybt under iron-deficient conditions.