Perham Michael, Stagg Loren, Wittung-Stafshede Pernilla
Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77251, USA.
FEBS Lett. 2007 Oct 30;581(26):5065-9. doi: 10.1016/j.febslet.2007.09.049. Epub 2007 Oct 1.
Here we show that increased amount of secondary structure is acquired in the folded states of two structurally-different proteins (alpha-helical VlsE and alpha/beta flavodoxin) in the presence of macromolecular crowding agents. The structural content of flavodoxin and VlsE is enhanced by 33% and 70%, respectively, in 400 mg/ml Ficoll 70 (pH 7, 20 degrees C) and correlates with higher protein-thermal stability. In the same Ficoll range, there are only small effects on the unfolded-state structures of the proteins. This is the first in vitro assessment of crowding effects on the native-state structures at physiological conditions. Our findings imply that for proteins with low intrinsic stability, the functional structures in vivo may differ from those observed in dilute buffers.
在此我们表明，在存在大分子拥挤剂的情况下，两种结构不同的蛋白质（α-螺旋VlsE和α/β型黄素氧还蛋白）在折叠状态下获得了更多的二级结构。在400 mg/ml聚蔗糖70（pH 7，20摄氏度）中，黄素氧还蛋白和VlsE的结构含量分别提高了33%和70%，且与更高的蛋白质热稳定性相关。在相同的聚蔗糖浓度范围内，对蛋白质的未折叠状态结构只有微小影响。这是首次在生理条件下对拥挤效应在天然状态结构上的体外评估。我们的研究结果表明，对于内在稳定性较低的蛋白质，其体内的功能结构可能与在稀缓冲液中观察到的不同。
