Effects of Fe3+ and Zn2+ on the Structural and Thermodynamic Properties of a Soybean ASR Protein
Effects of Fe3+ and Zn2+ on the Structural and Thermodynamic Properties of a Soybean ASR Protein
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Fe3 和 Zn2 对大豆 ASR 蛋白结构和热力学性质的影响
DOI：
10.1271/bbb.120666
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发表时间：
2013-03-01
影响因子：
1.6
通讯作者：
Zheng, Yi-Zhi
中科院分区：
文献类型：
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作者：
Li, Ran-Hui;Liu, Guo-Bao;Zheng, Yi-Zhi
脱落酸诱导蛋白、胁迫诱导蛋白和成熟诱导蛋白（ASR）在保护植物免受非生物胁迫中起着重要作用。已知一些ASR蛋白的功能通过与金属离子结合来调节。在这项研究中，我们证明了未标记的全长大豆（Glycine max）ASR蛋白（GmASR）可以结合Fe（3+），Ni（2+），Cu（2+）和Zn（2+）。通过内源荧光分析进一步证实了GmASR与Fe（3+）和Zn（2+）的直接结合特性。GmASR蛋白具有3个Fe（3+）结合位点，而只有2个Zn（2+）结合位点。在水溶液中，GmASR呈天然无序状态，Fe（3+）存在时，GmASR保持无序状态，而Zn（2+）存在时，GmASR发生聚集。EDTA螯合Zn（2+）后，聚集的GmASR蛋白部分溶解。GmASR在体外表现出Fe（3+）结合依赖的抗氧化活性。我们推测，GmASR因此保护免受氧化损伤的缓冲金属离子，从而减轻金属毒性在植物细胞在应激条件下。
Abscisic acid-, stress-, and ripening-induced (ASR) protein play important roles in protecting plants from abiotic stress. The functions of some ASR proteins are known to be modulated by binding to metal ions. In this study, we demonstrated that the non-tagged full-length soybean (Glycine max) ASR protein (GmASR) can bind Fe(3+), Ni(2+), Cu(2+), and Zn(2+). The direct binding properties of GmASR to Fe(3+) and Zn(2+) were further confirmed by intrinsic fluorescence assays. The GmASR protein was found to have three Fe(3+) binding sites but only two Zn(2+) binding sites. Natively disordered in aqueous solution, GmASR remained disordered in the presence of Fe(3+), but was found to aggregate in the presence of Zn(2+). The aggregated GmASR protein was partially resolubilized after Zn(2+) was chelated by EDTA. GmASR exhibited Fe(3+)-binding-dependent antioxidant activity in vitro. We speculate that GmASR thus protects against oxidation damage by buffering metal ions, thus alleviating metal toxicity in plant cells under stressed conditions.