Department of Chemistry & Biochemistry , University of California Santa Barbara , Santa Barbara , California 93106-9510 , United States.
J Nat Prod. 2019 Apr 26;82(4):990-997. doi: 10.1021/acs.jnatprod.8b01073. Epub 2019 Mar 14.
Identified through a bioinformatics approach, a nonribosomal peptide synthetase gene cluster in Alcanivorax pacificus encodes the biosynthesis of the new siderophore pacifibactin. The structure of pacifibactin differs markedly from the bioinformatic prediction and contains four bidentate metal chelation sites, atypical for siderophores. Genome mining and structural characterization of pacifibactin is reported herein, as well as characterization of pacifibactin variants accessible due to a lack of adenylation domain fidelity during biosynthesis. A spectrophotometric titration of pacifibactin with Fe(III) and C NMR spectroscopy of the Ga(III)-pacifibactin complex establish 1:1 metal:pacifibactin coordination and reveal which of the bidentate binding groups are coordinated to the metal. The photoreaction of Fe(III)-pacifibactin, resulting from Fe(III) coordination of the β-hydroxyaspartic acid ligands, is reported.
通过生物信息学方法鉴定，太平洋阿克氏菌中的非核糖体肽合成酶基因簇编码新的铁载体 pacifibactin 的生物合成。Pacifibactin 的结构与生物信息学预测明显不同，含有四个双齿金属螯合位点，这是非铁载体的典型特征。本文报道了 pacifibactin 的基因组挖掘和结构特征，以及由于生物合成过程中腺苷酸化结构域保真度缺失而产生的 pacifibactin 变体的特征。Pacifibactin 与 Fe(III)的分光光度滴定和 Ga(III)-pacifibactin 配合物的 C NMR 光谱研究建立了 1:1 的金属：pacifibactin 配位，并揭示了双齿配位基团与金属的配位方式。报道了 Fe(III)-pacifibactin 的光反应，这是由于 β-羟基天冬氨酸配体与 Fe(III)的配位所致。
