论文标题
doming和自旋级联铁：飞秒X射线吸收和X射线发射研究
Doming and spin cascade in Ferric Haems: Femtosecond X-ray Absorption and X-ray Emission Studies
论文作者
论文摘要
结构功能关系是生物学的核心，主要蛋白质变形与特定功能相关。在血红素蛋白的情况下，DOMING与血红蛋白和肌球蛋白的呼吸功能有关，而荷叶蛋白与电子转移过程相关，例如细胞色素C（CytT C）。后者的确已经演变为人类中重要的电子转移蛋白。它以其黑色的形式，在光激发时经历配体释放并归因，但其铁形式并未释放远端配体，而返回基态的返回已归因于热松弛。 Here, by combining femtosecond Fe K-edge X-ray absorption near-edge structure (XANES) studies and femtosecond Fe Kalpha and Kbeta X-ray emission spectroscopy (XES), we demonstrate that the photocycle of ferric Cyt c is entirely due to a cascade among excited spin states of the Iron ion, causing the ferric heme to undergo doming, which we identify for the first time.我们还认为，这种模式对于所有血液中都是共同的，这提出了这种蛋白质中穹顶的生物学相关性问题。
The structure-function relationship is at the heart of biology and major protein deformations are correlated to specific functions. In the case of heme proteins, doming is associated with the respiratory function in hemoglobin and myoglobin, while ruffling has been correlated with electron transfer processes, such as in the case of Cytochrome c (Cyt c). The latter has indeed evolved to become an important electron transfer protein in humans. In its ferrous form, it undergoes ligand release and doming upon photoexcitation, but its ferric form does not release the distal ligand, while the return to the ground state has been attributed to thermal relaxation. Here, by combining femtosecond Fe K-edge X-ray absorption near-edge structure (XANES) studies and femtosecond Fe Kalpha and Kbeta X-ray emission spectroscopy (XES), we demonstrate that the photocycle of ferric Cyt c is entirely due to a cascade among excited spin states of the Iron ion, causing the ferric heme to undergo doming, which we identify for the first time. We also argue that this pattern is common to all ferric haems, raising the question of the biological relevance of doming in such proteins.
