STEREOCHEMICAL CHARACTERIZATION OF RHIZOFERRIN AND IDENTIFICATION OF ITS DEHYDRATION PRODUCTS
STEREOCHEMICAL CHARACTERIZATION OF RHIZOFERRIN AND IDENTIFICATION OF ITS DEHYDRATION PRODUCTS
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DOI：
10.1007/bf01061320
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发表时间：
1992-09-01
期刊：
影响因子：
3.5
通讯作者：
WINKELMANN, G
中科院分区：
文献类型：
--
作者：
DRECHSEL, H;JUNG, G;WINKELMANN, G
采用制备高效液相色谱法对多羧酸铁铁、根铁蛋白及其脱水产物进行了分离，并用C-13-NMR、H-1-NMR、紫外、圆二色性（CD）、红外光谱和毛细管电泳对产物进行了表征。核磁共振谱对所有碳原子和质子的分配证实了根铁蛋白的结构，并证明了脱水副产物亚胺根铁蛋白和双胺根铁蛋白的存在。在毛细管电泳中，亚胺形式也以其迁移性为特征。紫外光谱显示pH值大于3时铁与配体的比例为1:1。根据金属配体电荷转移带在335 nm处的最大吸收，计算出铁根铁蛋白的摩尔消光系数为2300 M-1 cm-1。CD测量结果表明，两种柠檬酸残基的四碳原子呈R，R构型，根铁蛋白的铁配合物在金属中心周围呈λ构型。
The polycarboxylate siderophore, rhizoferrin, and its dehydration products were separated by preparative HPLC and characterized by C-13-NMR, H-1-NMR, UV, circular dichroism (CD) and IR spectroscopy, and also by capillary electrophoresis. Assignment of all carbon atoms and protons by NMR spectra confirmed the structure of rhizoferrin and gave evidence for the presence of the cyclized dehydration byproducts, imidorhizoferrin and bis-imidorhizoferrin. The imido forms were also characterized by their mobility during capillary electrophoresis. UV spectra revealed a 1:1 iron:ligand ratio above pH 3. Based on the absorption maximum of the metal ligand charge transfer band at 335 nm a molar extinction coefficient of 2300 M-1 cm-1 was calculated for ferric rhizoferrin. CD measurements revealed that the quarternary carbon atoms of the two citric acid residues possess an R,R configuration and that the iron complex of rhizoferrin adopts a LAMBDA configuration around the metal center.