Department of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.
Org Biomol Chem. 2013 Jul 28;11(28):4686-94. doi: 10.1039/c3ob40536b. Epub 2013 Jun 11.
Scabichelin and turgichelin, novel tris-hydroxamate siderophores, were isolated from Streptomyces antibioticus NBRC 13838/Streptomyces scabies JCM 7914 and Streptomyces turgidiscabies JCM 10429, respectively. The planar structures of scabichelin and turgichelin were elucidated by mass spectrometry, and 1- and 2-D NMR spectroscopic analyses of their gallium(III) complexes. The relative and absolute stereochemistry of the metabolites was determined by the modified Marfey's method in conjunction with computational modelling and NOESY NMR analysis of Ga-scabichelin and Ga-turgichelin. Genome sequence analysis of the plant pathogen Streptomyces scabies 87.22 identified a gene cluster containing a gene encoding a nonribosomal peptide synthetase (NRPS) that was predicted to direct the production of a pentapeptide with structural similarities to scabichelin and turgichelin. Comparative LC-MS/MS analyses of iron-deficient culture supernatants from wild type S. scabies 87.22 and a mutant in which the NRPS gene had been disrupted, and scabichelin purified from S. antibioticus, showed that scabichelin is the metabolic product of the cryptic gene cluster, strongly suggesting that it functions as a siderophore.
沙比西林和图尔吉西林是从链霉菌属抗生素 NBRC 13838/链霉菌疮痂 JCM 7914 和链霉菌肿胀疮痂 JCM 10429 中分离得到的两种新型三羟肟酸类铁载体。通过质谱、其镓（III）配合物的 1D 和 2D NMR 光谱分析，阐明了沙比西林和图尔吉西林的平面结构。通过改良的 Marfey 法结合计算建模和 Ga-沙比西林和 Ga-图尔吉西林的 NOESY NMR 分析，确定了代谢物的相对和绝对立体化学。对植物病原体疮痂链霉菌 87.22 的基因组序列分析鉴定出一个基因簇，其中包含一个编码非核糖体肽合酶（NRPS）的基因，该基因预测可指导产生与沙比西林和图尔吉西林结构相似的五肽。野生型疮痂链霉菌 87.22 和敲除 NRPS 基因的突变体在缺铁培养上清液中的 LC-MS/MS 比较分析，以及从链霉菌属抗生素中分离出的沙比西林表明，沙比西林是该隐匿基因簇的代谢产物，强烈表明它作为一种铁载体发挥作用。
