A two-dimensional view of the folding energy landscape of cytochrome c.-猫眼课题宝

细胞色素 c 折叠能量景观的二维视图。

DOI：

10.1073/pnas.0604712103

发表时间：

2006

期刊：

Proceedings of the National Academy of Sciences of the United States of America.

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

Werner,JamesH;Joggerst,Raymond;Dyer,RBrian;Goodwin,PeterM

采用时间相关单光子计数（TCSPC）和荧光相关光谱（FCS）相结合的方法，研究了酿酒酵母细胞色素（Cytc）的酸变性状态与天然结构之间的转变.事实证明，这些技术的协同使用比单独使用更强大，产生了细胞色素c折叠能量景观的二维图像。TCSPC测量蛋白质的血红素和共价连接的染料分子在残基C102（一个折叠反应坐标）之间的距离分布，而FCS测量的流体动力学半径（第二折叠反应坐标）的蛋白质在一定范围内的pH值。这两个独立的测量提供了关于蛋白质构象的补充信息。我们看到的证据，一个明确定义的折叠中间体的酸复性折叠途径，这种蛋白质的寿命分布所需的，以适应TCSPC数据反映。此外，FCS研究表明，这种中间状态与未折叠的结构处于动态平衡状态，在大约30 μs的时间尺度上发生了进入和离开这种中间状态的构象波动。

Time-correlated single photon counting (TCSPC) was combined with fluorescence correlation spectroscopy (FCS) to study the transition between acid-denatured states and the native structure of cytochromec(Cytc) fromSaccharomyces cerevisiae. The use of these techniques in concert proved to be more powerful than either alone, yielding a two-dimensional picture of the folding energy landscape of Cytc. TCSPC measured the distribution of distances between the heme of the protein and a covalently attached dye molecule at residue C102 (one folding reaction coordinate), whereas FCS measured the hydrodynamic radius (a second folding reaction coordinate) of the protein over a range of pH values. These two independent measurements provide complimentary information regarding protein conformation. We see evidence for a well defined folding intermediate in the acid renaturation folding pathway of this protein reflected in the distribution of lifetimes needed to fit the TCSPC data. Moreover, FCS studies revealed this intermediate state to be in dynamic equilibrium with unfolded structures, with conformational fluctuations into and out of this intermediate state occurring on an ≈30-μs time scale.