Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr 8, 07743, Jena, Germany.
New address: Department of Analytical Chemistry, Faculty of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245, Bialystok, Poland.
Chemistry. 2021 Feb 5;27(8):2724-2733. doi: 10.1002/chem.202003842. Epub 2021 Jan 14.
Gramibactin (GBT) is an archetype for the new class of diazeniumdiolate siderophores, produced by Paraburkholderia graminis, a cereal-associated rhizosphere bacterium, for which a detailed solution thermodynamic study exploring the iron coordination properties is reported. The acid-base behavior of gramibactin as well as its complexing ability toward Fe was studied over a wide range of pH values (2≤pH≤11). For the latter the ligand-competition method employing EDTA was used. Only two species are formed: [Fe(GBT)] (pH 2 to 9) and [Fe(GBT)(OH) ] (pH≥9). The formation of [Fe(GBT)] and its occurrence in real systems was confirmed by LC-HRESIMS analysis of the bacteria culture broth extract. The sequestering ability of gramibactin was also evaluated in terms of the parameters pFe and pL . Gramibactin exhibits a higher sequestering ability toward Fe than EDTA and of the same order of magnitude as hydroxamate-type microbial siderophores, but smaller than most of the catecholate-type siderophores and much higher than the most known phytosiderophores.
Gramibactin (GBT) 是新型二氮烯二羟酸盐类铁载体的原型，由谷物根际细菌 Paraburkholderia graminis 产生，本文报道了对其进行详细溶液热力学研究，以探索其铁配位特性。研究了 gramibactin 的酸碱行为及其在很宽的 pH 值范围内（2≤pH≤11）对 Fe 的络合能力。对于后者，使用 EDTA 的配体竞争方法。只形成了两种物种：[Fe(GBT)]（pH 2 到 9）和[Fe(GBT)(OH)]（pH≥9）。通过对细菌培养液提取物的 LC-HRESIMS 分析，确认了[Fe(GBT)]的形成及其在实际系统中的存在。还根据 pFe 和 pL 参数评估了 gramibactin 的螯合能力。与 EDTA 相比，gramibactin 对 Fe 的螯合能力更高，与羟肟酸盐型微生物铁载体处于同一数量级，但小于大多数儿茶酚型铁载体，远高于大多数已知的植物铁载体。
