来自Desulfoarculus baarsii的超氧化还原酶中的Fe3+-氧化物结合与pH值依赖的光谱变化有关
Christelle Mathé1, Vincent Nivière, Tony A Mattioli
1Laboratoire de Biophysique du Stress Oxydant, SBE/DBJC and CNRS URA 2096, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France.
Journal of the American Chemical Society
|November 25, 2005
概括
研究了超氧化还原酶 (SOR) 活性部位结构. 在基本pH下形成高旋转Fe3+-OH物种,被确定为酶性转换中的关键基.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 酶学 是一种酶学.
背景情况:
- 超氧化还原酶 (SOR) 对于将超氧化基 (O2*-) 减少为过氧化 (H2O2) 是至关重要的.
- 该酶具有独特的非血红素Fe2+活性位点,具有[His4 Cys]协调.
- 在其电子吸收光谱中,SOR表现出pH依赖的性过渡.
研究的目的:
- 为了阐明在Desulfoarculus baarsii SOR中依赖pH的性过渡的分子基础.
- 为了确定参与性转换的未识别的基 (B-).
- 了解SOR催化循环中活性位点物种化的作用.
主要方法:
- 使用共振拉曼光谱来探测活性部位结构.
- 在pH范围内对野生类型和突变SOR酶 (E47A,K48I) 的光谱分析.
- 频谱变化与电子吸收带移动的相关性.
主要成果:
- 在基本pH条件下,在活性部位确定了一种高旋转Fe3+-OH物种.
- 这种Fe3+-OH物种与560nm的吸收带直接相关.
- Fe3+-OH物种的质子化将吸收带转移到644nm,与水联体一致.
结论:
- 参与性转换的未识别的基 (B-) 被确定为高旋转Fe3+-OH物种.
- 性过渡涉及这个基连接体的质子化/脱质子化.
- 这一发现为Superoxide Reductase的催化机制提供了关键的见解.
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