Center for Oxygen Microscopy and Imaging, Chemistry Department, Aarhus University, DK-8000, Århus, Denmark.
J Am Chem Soc. 2011 May 11;133(18):7166-73. doi: 10.1021/ja2010708. Epub 2011 Apr 14.
Singlet molecular oxygen, O(2)(a(1)Δ(g)), is an intermediate in a variety of processes pertinent to the function of biological systems, including events that result in cell death. Many of these processes involve a reaction between singlet oxygen and a given protein. It is acknowledged that the behavior of a protein can change upon reaction with singlet oxygen, as a result of a structural alteration and/or a direct chemical modification of an active site. However, the converse, where one considers how the behavior of singlet oxygen can be altered by changes in protein structure, has received little attention. In this report, we use a variety of proteins to demonstrate how the rate constant for singlet oxygen removal by a protein responds to (a) protein denaturation, (b) macromolecular crowding of the protein, (c) ligand binding by the protein, and (d) polymerization of the protein. From one perspective, the data show that the kinetics of singlet oxygen removal can be used to monitor protein dynamics. Most importantly, however, the data indicate that protein structural changes that either reveal or cloak a given amino acid residue can have a measurable effect on the overall rate constant for singlet oxygen removal which, in turn, can have ramifications for singlet-oxygen-mediated intracellular events that perturb cell function.
单线态氧，O(2)(a(1)Δ(g))，是与生物系统功能相关的各种过程的中间产物，包括导致细胞死亡的事件。许多这些过程涉及单线态氧与特定蛋白质之间的反应。人们认识到，蛋白质的行为在与单线态氧反应后会发生变化，这是由于结构改变和/或活性部位的直接化学修饰。然而，相反的情况，即考虑蛋白质结构的变化如何改变单线态氧的行为，却很少受到关注。在本报告中，我们使用各种蛋白质来证明蛋白质结构变化如何影响单线态氧去除的速率常数，具体包括：(a) 蛋白质变性；(b) 蛋白质的大分子拥挤；(c) 蛋白质与配体的结合；以及 (d) 蛋白质聚合。从一个角度来看，这些数据表明，单线态氧去除的动力学可用于监测蛋白质动力学。然而，最重要的是，数据表明，蛋白质结构的变化，无论是揭示还是隐藏特定的氨基酸残基，都可能对单线态氧去除的总速率常数产生可测量的影响，这反过来又可能对扰乱细胞功能的单线态氧介导的细胞内事件产生影响。
