Istituto I.S.O.F. (C.N.R.), via P. Gobetti 101, 40129 Bologna, Italy.
Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, via Belmeloro 8/2, 40126 Bologna, Italy.
Biomolecules. 2019 Nov 27;9(12):794. doi: 10.3390/biom9120794.
Model systems constituted by proteins and unsaturated lipid vesicles were used to gain more insight into the effects of the propagation of an initial radical damage on protein to the lipid compartment. The latter is based on liposome technology and allows measuring the unsaturated fatty acid content as a result of free radical stress on proteins. Two kinds of sulfur-containing proteins were chosen to connect their chemical reactivity with membrane lipid transformation, serum albumins and metallothioneins. Biomimetic systems based on radiation chemistry were used to mimic the protein exposure to different kinds of free radical stress and Raman spectroscopy to shed light on protein structural changes caused by the free radical attack. Among the amino acid residues, Cys is one of the most sensitive residues towards the attack of free radicals, thus suggesting that metal-Cys clusters are good interceptors of reactive species in metallothioneins, together with disulfides moieties in serum albumins. Met is another important site of the attack, in particular under reductive conditions. Tyr and Phe are sensitive to radical stress too, leading to electron transfer reactions or radical-induced modifications of their structures. Finally, modifications in protein folding take place depending on reactive species attacking the protein.
采用由蛋白质和不饱和脂质囊泡组成的模型系统，深入研究初始自由基损伤在蛋白质向脂质隔室传播过程中对脂质的影响。后者基于脂质体技术，可测量蛋白质自由基应激导致的不饱和脂肪酸含量。选择两种含硫蛋白质来连接它们的化学反应性与膜脂质转化，即血清白蛋白和金属硫蛋白。基于辐射化学的仿生系统用于模拟蛋白质暴露于不同类型的自由基应激，拉曼光谱用于阐明自由基攻击引起的蛋白质结构变化。在氨基酸残基中，半胱氨酸是最易受到自由基攻击的残基之一，因此金属-半胱氨酸簇是金属硫蛋白中活性物质的良好捕获剂，与血清白蛋白中的二硫键部分一起。蛋氨酸也是攻击的另一个重要部位，特别是在还原条件下。色氨酸和苯丙氨酸对自由基应激也很敏感，导致电子转移反应或自由基诱导的结构修饰。最后，根据攻击蛋白质的活性物质，蛋白质折叠发生变化。
