STRUCTURE OF CYTOCHROME P450 REDOX PARTNER COMPLEXES

P450酶与它们的氧化还原配偶体的相互作用以及 电子转移机制是最重要和最有趣的 P450研究领域的问题。四种晶体结构 细菌P450，微粒体P450还原酶的催化结构域，和 putidaredoxin NMR结构是已知的。然而，这些知识 结构并不能直接回答蛋白质在哪里以及如何相互作用。 由于晶体学中其他电子传递蛋白的相互作用， 电子转移复合物被证明是特异性的，并与之相关， 发生在溶液中，我们建议，P450-氧化还原结晶 伴侣复合物将能够鉴定相互作用位点， 结合时发生的构象变化，以及来自 一个辅因子到另一个辅因子。P450 cam电子转移系统和 黄细胞色素P450 BM-3血红素/FMN结合结构域， 微粒体P450和还原酶的结构类似物是最好的 I类和II类结晶试验的候选物 单加氧酶系统。 使共价连接的血红素/FMN结合结构域和 血红素结合域和FMN结合域之间的非共价复合物 P450 BM-3，我们处于解决这些结构的绝佳位置， 这无疑会让我们更好地理解 和微粒体P450依赖性单加氧酶系统的功能。

Interaction of the P450 enzymes with their redox partners and the mechanism of electron transfer are the most important and intriguing problems in the area of P450 research. The crystal structures of four bacterial P450s, the catalytical domain of microsomal P450 reductase, and the NMR structure of putidaredoxin are known. However, knowledge of these structures does not directly answer where and how the proteins interact. Since interaction of other electron transfer proteins in crystallographic electron transfer complexes was shown to be specific and relevant to that occurring in a solution, we propose that crystallization of P450-redox partner complexes will enable the identification of interaction sites, conformation changes occurring upon binding, and the electron pathway from one co-factor to another. The P450cam electron transfer system and the heme/FMN-binding domain of flavocytochrome P450BM-3, a functional and structural analog to microsomal P450s and reductase, are the best candidates for crystallization trials of Class I and Class II monooxygenase systems, respectively. Having crystallized both the covalently linked heme/FMN-binding domain and the non-covalent complex between the separate heme-and FMN-binding domains of P450BM-3, we are in an excellent position to solve these structures, which will, undoubtedly, lead to our better understanding of the mechanism and function of microsomal P450-dependent monooxygenase systems.