Sanfelice Domenico, Politou Anastasia, Martin Stephen R, De Los Rios Paolo, Temussi Pierandrea, Pastore Annalisa
National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK.
Phys Biol. 2013 Aug;10(4):045002. doi: 10.1088/1478-3975/10/4/045002. Epub 2013 Aug 2.
Crowding and confinement can affect protein stability, favouring the more compact species amongst the folded and unfolded conformations. An unbiased assessment of the relative efficacy of crowded and confined environments has been hampered so far by the paucity of homogeneous comparisons on the same protein. This paper reports spectroscopic studies on yeast frataxin (Yfh1), a protein which provides an excellent model system for stability studies since it undergoes both cold and heat denaturation at measurable temperatures. The stability of Yfh1 was evaluated in the presence of Ficoll 70 and inside the cavities of polyacrylamide gels as means of mimicking crowding and confinement. We find that both effects influence the thermal stability of Yfh1 to a comparable extent thus providing the first direct comparison of crowding and confinement on the same protein. Thanks to the measurement of the full stability curve we also present the first thermodynamic characterization of the stability of a protein in crowding conditions.
拥挤和受限环境会影响蛋白质稳定性，在折叠和未折叠构象中更倾向于更紧凑的物种。到目前为止，由于缺乏对同一蛋白质的同类比较，对拥挤和受限环境的相对功效的无偏见评估受到了阻碍。本文报道了对酵母铁硫蛋白（Yfh1）的光谱学研究，该蛋白是稳定性研究的优秀模型系统，因为它在可测量温度下会发生冷变性和热变性。通过模拟拥挤和受限环境，在存在聚蔗糖70的情况下以及在聚丙烯酰胺凝胶的孔内评估了Yfh1的稳定性。我们发现这两种效应在相当程度上影响Yfh1的热稳定性，从而首次对同一蛋白质的拥挤和受限环境进行了直接比较。由于测量了完整的稳定性曲线,我们还首次给出了蛋白质在拥挤条件下稳定性的热力学特征。
