皮洛科克的[NiFe]-酶表现出一种新型的氧气耐受性
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Patrick Kwan1, Chelsea L McIntosh1, David P Jennings1
1Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287, United States.
Journal of the American Chemical Society
|October 6, 2015
概括
这项研究描述了氧气如何影响特定的酶Pyrococcus furiosus酶I (PfSHI). 与其他化酶不同,PfSHI具有显著的氧弹性,特别是在高温下.
科学领域:
- 生物化学
- 酵素学
- 生物能源
背景情况:
- [NiFe]-酶是代谢的关键酶.
- 可溶性3组[NiFe]-酶,如PfSHI,已知具有耐氧性,但缺乏1组酶中发现的保护性 [4Fe3S]集群.
- 了解氧气对这些酶的影响对于生物技术应用至关重要.
研究的目的:
- 从电化学上描述Pyrococcus furiosus (PfSHI) 的酶I的耐氧性,这是一个可溶的3组[NiFe]酶.
- 调查PfSHI对氧气暴露的反应的温度依赖性.
- 提出一个新的分类 ("耐氧") 和一个机械模型,用于这种酶类的耐氧性.
主要方法:
- 测量氧化活性时使用了时测量仪.
- 在短时间和长时间暴露于不同氧度和温度后评估了酶活性.
- 分析了重新激活的动力学,以确定不同的非活性状态.
主要成果:
- 在短时间接触氧气后,PfSHI表现出氧气耐受性,在广泛的温度范围内 (15-80°C) 保持活性.
- 氧气暴露导致至少两种,甚至可能三种不同的无活性状态的形成.
- 酶对持续氧气暴露的抗性高度依赖温度,在80°C保持显著活性,但在25°C丧失活性.
- 短暂停用后的活性化是快速的 (< 150秒),而持续停用后的活性化是缓慢的 (几十分钟).
结论:
- 建议将PfSHI作为"耐氧",这是一个与"耐氧"一组酶不同的新类别.
- 建议在可溶性组3[NiFe]酶中采用一种新的氧气耐受性机制,独立于 [4Fe3S] 集群.
- 这些发现需要对[NiFe]酶的氧耐受性和失活路径进行修订.
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