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Iron Coordination Properties of Gramibactin as Model for the New Class of Diazeniumdiolate Based Siderophores
Author(s) -
Gama Sofia,
Hermenau Ron,
Frontauria Mariachiara,
Milea Demetrio,
Sammartano Silvio,
Hertweck Christian,
Plass Winfried
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202003842
Subject(s) - siderophore , rhizosphere , chemistry , ligand (biochemistry) , chelation , metal , stereochemistry , bacteria , inorganic chemistry , organic chemistry , biology , biochemistry , receptor , genetics , gene
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 3+ 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) 2 ] 3− (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 0.5 . Gramibactin exhibits a higher sequestering ability toward Fe 3+ 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.