Characterization of PlGoxB, a flavoprotein required for cysteine tryptophylquinone biosynthesis in glycine oxidase from Pseudoalteromonas luteoviolacea.
Characterization of PlGoxB, a flavoprotein required for cysteine tryptophylquinone biosynthesis in glycine oxidase from Pseudoalteromonas luteoviolacea.
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PlGoxB 的表征，PlGoxB 是黄黄假交替单胞菌甘氨酸氧化酶中半胱氨酸色氨酸醌生物合成所需的黄素蛋白。
DOI：
10.1016/j.abb.2019.108110
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发表时间：
2019
影响因子：
3.9
通讯作者：
Davidson,VictorL
中科院分区：
文献类型：
--
作者：
Mamounis,KyleJ;Ma,Zhongxin;Sanchez-Amat,Antonio;Davidson,VictorL
LodA样蛋白是具有蛋白质衍生的半胱氨酸对苯醌（CTQ）辅基的氧化酶。在假交替单胞菌黄紫甘氨酸氧化酶（PlGoxA）中，CTQ的生物合成需要由PlgoxB编码的修饰酶催化的翻译后修饰。表达PlGoxB蛋白并显示其具有黄素辅因子。PlGoxB在溶液中不稳定，因为它容易失去黄素并沉淀。通过与过量的FAD或等浓度的prePlGoxA（作为其底物的前体蛋白）一起孵育，PlGoxB沉淀显著减少。与此相反，成熟的CTQ轴承PlGoxA没有稳定作用。使用烷基卤酶CmIS的结构产生PlGoxB的同源性模型。模型中PlGoxB的FAD结合位点与模板结构几乎相同。PlGoxB中结合的FAD具有显著的溶剂暴露，与观察到的失去FAD的趋势一致。这也表明，prePlGoxA与PlGoxB在暴露的FAD结合位点处的相互作用可以防止观察到的FAD损失和随后的PlGoxB沉淀。假定的PlGoxB-prePlGoxA复合物的对接模型与这些假设一致。实验结果和计算分析暗示的结构特征，有助于其稳定性和功能的PlGoxB。
LodA-like proteins are oxidases with a protein-derived cysteine tryptophylquinone (CTQ) prosthetic group. InPseudoalteromonasluteoviolaceaglycine oxidase (PlGoxA), CTQ biosynthesis requires post-translational modifications catalyzed by a modifying enzyme encoded by PlgoxB. The PlGoxB protein was expressed and shown to possess a flavin cofactor. PlGoxB was unstable in solution as it readily lost the flavin and precipitated. PlGoxB precipitation was significantly reduced by incubation with either excess FAD or an equal concentration of prePlGoxA, the precursor protein that is its substrate. In contrast, the mature CTQ-bearing PlGoxA had no stabilizing effect. A homology model of PlGoxB was generated using the structure of Alkylhalidase CmIS. The FAD-binding site of PlGoxB in the model was nearly identical to that of the template structure. The bound FAD in PlGoxB had significant solvent exposure, consistent with the observed tendency to lose FAD. This also suggested that interaction of prePlGoxA with PlGoxB at the exposed FAD-binding site could prevent the observed loss of FAD and subsequent precipitation of PlGoxB. A docking model of the putative PlGoxB-prePlGoxA complex was consistent with these hypotheses. The experimental results and computational analysis implicate structural features of PlGoxB that contribute to its stability and function.