Koster M, Ovaa W, Bitter W, Weisbeek P
Department of Molecular Cell Biology, Utrecht University, The Netherlands.
Mol Gen Genet. 1995 Oct 25;248(6):735-43. doi: 10.1007/BF02191714.
Under iron limitation Pseudomonas putida WCS358 produces a fluorescent siderophore, pseudobactin 358, which, after complexing iron, is transported back into the cell via the specific outer membrane receptor PupA. In addition, this strain has the capacity to take up iron via a large variety of siderophores produced by other fluorescent pseudomonads. Putative receptor genes for such siderophores were identified in the chromosome of strain WCS358 by PCR using primers matching two domains conserved in four ferric pseudobactin receptors, including PupA. Eleven amplification products within the expected size range were obtained. Sequence analysis confirmed that the products were derived from genes encoding outer membrane receptors. Two complete receptor genes were isolated from a genomic library of P. putida WCS358. Both protein products are involved in the transport of a limited number of specific ferric pseudobactins. These results indicate that the ability of P. putida WCS358 to exploit many different heterologous pseudobactins is related to the presence of multiple outer membrane receptor proteins.
在铁限制条件下，恶臭假单胞菌WCS358产生一种荧光铁载体——假铁载体358，其与铁络合后，通过特异性外膜受体PupA转运回细胞内。此外，该菌株能够通过其他荧光假单胞菌产生的多种铁载体来摄取铁。通过使用与包括PupA在内的四种铁假铁载体受体中两个保守结构域匹配的引物进行PCR，在菌株WCS358的染色体中鉴定出了此类铁载体的假定受体基因。获得了11个预期大小范围内的扩增产物。序列分析证实这些产物源自编码外膜受体的基因。从恶臭假单胞菌WCS358的基因组文库中分离出两个完整的受体基因。这两种蛋白质产物都参与了有限数量的特定铁假铁载体的转运。这些结果表明，恶臭假单胞菌WCS358利用多种不同异源假铁载体的能力与多种外膜受体蛋白的存在有关。
