STRUCTURE OF FERRIC PSEUDOBACTIN, A SIDEROPHORE FROM A PLANT-GROWTH PROMOTING PSEUDOMONAS
STRUCTURE OF FERRIC PSEUDOBACTIN, A SIDEROPHORE FROM A PLANT-GROWTH PROMOTING PSEUDOMONAS
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DOI：
10.1021/bi00525a025
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
VANDERHELM, D
中科院分区：
文献类型：
--
作者：
TEINTZE, M;HOSSAIN, MB;VANDERHELM, D
植物生长促进剂假单胞菌B10及其黄绿色荧光铁转运剂(铁载体)假黄素可促进马铃薯生长并控制某些植物病原微生物。用单晶X-射线衍射法，利用计数器数据确定了假细菌蛋白的结构。该结构由线性六肽L-Lys-D-threo-.beta.-OH-Asp-L-Ala-D-allo-Thr-L-Ala-D-N.delta.-OH-Orn，组成，其中鸟氨酸的N-β-OHN与C-末端的羧基环化，赖氨酸的N-β-氨基通过酰胺键连接到荧光喹啉衍生物上。铁-螯合基团包括源自N-β-羟基鸟氨酸的羟甲酸基、源于β-羟基天冬氨酸的α-羟基酸和源于喹啉部分的邻二羟基芳香族基团。金属螯合配体和交替的L氨基酸和D-氨基酸的结合是不寻常的。假硼蛋白结晶为单一配位异构体，绝对构型为LAMBDA。这是第一次对荧光铁载体进行结构测定。在晶体结构中，假性铁形成了二聚体，构成了不对称单元。不对称单元还含有26个水分子。二聚体中的分子通过假2重对称轴联系在一起。从水平衡的吡啶-醋酸缓冲溶液中得到红棕色的假硼铁(C42H57N12O16Fe.cntdot.13H2O)晶体，其空间群为I2，a=29.006(23)，b=14.511(13)，c=28.791(21)，β。=96.06(5)度在-135(2)℃下，对于8个分子/单位晶胞，计算密度为1.38g/cm~3；观察密度为1.40g/cm~3。用最小二乘法对所有非氢原子的各向异性热参数进行了修正，最终的R因子为0.08(8989个观察到的反射)。
Plant growth promoting Pseudomonas B10 and its yellow-green, fluorescent Fe transport agent (siderophore) pseudobactin enhance the growth of the potato and control certain phytopathogenic microorganisms. The structure of pseudobactin was determined by single-crystal X-ray diffraction methods using counter data. The structure consisted of a linear hexapeptide, L-Lys-D-threo-.beta.-OH-Asp-L-Ala-D-allo-Thr-L-Ala-D-N.delta.-OH-Orn, in which the N.delta.-OH N of the ornithine was cyclized with the C-terminal carboxyl group and the N.epsilon.-amino group of the lysine was linked via an amide bond to a fluorescent quinoline derivative. The Fe-chelating groups consisted of a hydroxamate group derived from N.delta.-hydroxyornithine, an .alpha.-hydroxy acid derived from .beta.-hydroxyaspartic acid and an o-dihydroxy aromatic group derived from the quinoline moiety. The combination of metal-chelating ligands and the alternating L- and D-amino acids was unusual. Pseudobactin crystallized as a single coordination isomer with the .LAMBDA. absolute configuration. This is the first structural determination of a fluorescent siderophore. In the crystal structure, ferric pseudobactin formed a dimer, which constituted the asymmetric unit. The asymmetric unit also contained 26 water molecules. The molecules in the dimer were related by a pseudo-2-fold symmetry axis. Red-brown crystals of ferric pseudobactin (C42H57N12O16Fe.cntdot.13H2O), obtained from pyridine-acetic acid buffer solution equilibrated with water, conformed to space group I2 with a = 29.006 (23) .ANG., b= 14.511 (13) .ANG., c = 28.791 (21) .ANG. and .beta. = 96.06 (5).degree. at -135 (2) .degree.C. For 8 molecules/unit cell, the calculated density was 1.38 g/cm3; the observed density was 1.40 g/cm3. The structure was refined by least-squares methods with anisotropic thermal parameters for all nonhydrogen atoms to a final R factor of 0.08 (8989 observed reflections).