STRUCTURE AND DOMAIN MOTIONS RELEVANT TO INTRAMOLECULAR ELECTRON TRANSFER IN SUL

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 含钼酶广泛存在，催化原子转移反应与分子内电子转移(IET)相结合。亚硫酸盐氧化酶是钼酶家族中的典型成员，在周转过程中进行内切酶，其速率约为2000 S^-1。除了亚硫酸盐氧化酶外，所有钼酶的晶体结构都显示出电子供体和受体位置的分离，在IET的预期范围内。然而，对于亚硫酸盐氧化酶，晶体结构显示C-末端结构域中的Mo供体位置和N-末端结构域中的接受电子基团之间有很大的~32°间隔。如此大的分离似乎排除了以观察到的速率进行IET的可能性。为了促进IET，已提出将N-末端结构域与更大的C-末端结构域(更紧密的构象)对接，但没有实验证据证明这一点。拟议的研究旨在提供这样的证据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Molybdenum-containing enzymes are widespread, catalyzing atom transfer reactions coupled to intramolecular electron transfer (IET). Sulfite oxidase is the prototypical member of one major family of Mo enzymes, and carries out IET during turnover with a rate of ~2000 s^-1. With the sole exception of sulfite oxidase, all Mo enzyme crystal structures show separations of electron donor and acceptor sites well within the expected range for IET. For sulfite oxidase, however, crystal structures show large separations of ~32 ¿ between the Mo donor site in the C-terminal domain and the electron-accepting group in the N-terminal domain. Such large separation would appear to preclude IET at the rates observed. Docking of the N-terminal domain with the larger C-terminal domain (a more compact conformation) has been proposed to facilitate IET however there is no experimental evidence for this. The proposed study seeks to provide such evidence.