Petersen Jan, Wilmann Pascal G, Beddoe Travis, Oakley Aaron J, Devenish Rodney J, Prescott Mark, Rossjohn Jamie
The Protein Crystallography Unit, School of Biomedical Sciences, Monash University, Victoria, Australia.
J Biol Chem. 2003 Nov 7;278(45):44626-31. doi: 10.1074/jbc.M307896200. Epub 2003 Aug 8.
We have crystallized and subsequently determined to 2.0-A resolution the crystal structure of eqFP611, a far red fluorescent protein from the sea anemone Entacmaea quadricolor. The structure of the protomer, which adopts a beta-can topology, is similar to that of the related monomeric green fluorescent protein (GFP). The quaternary structure of eqFP611, a tetramer exhibiting 222 symmetry, is similar to that observed for the more closely related red fluorescent protein DsRed and the chromoprotein Rtms5. The unique chromophore sequence (Met63-Tyr64-Gly65) of eqFP611, adopts a coplanar and trans conformation within the interior of the beta-can fold. Accordingly, the eqFP611 chromophore adopts a significantly different conformation in comparison to the chromophore conformation observed in GFP, DsRed, and Rtms5. The coplanar chromophore conformation and its immediate environment provide a structural basis for the far red, highly fluorescent nature of eqFP611. The eqFP611 structure extends our knowledge on the range of conformations a chromophore can adopt within closely related members of the green fluorescent protein family.
我们已经获得了来自海葵四色刺细胞虫（Entacmaea quadricolor）的远红荧光蛋白eqFP611的晶体，并随后将其晶体结构解析到了2.0埃的分辨率。原体采用β-桶拓扑结构，其结构与相关的单体绿色荧光蛋白（GFP）相似。eqFP611的四级结构是一个具有222对称性的四聚体，与关系更近的红色荧光蛋白DsRed和色素蛋白Rtms5的四级结构相似。eqFP611独特的发色团序列（Met63-Tyr64-Gly65）在β-桶折叠内部呈共面且反式构象。因此，与在GFP、DsRed和Rtms5中观察到的发色团构象相比，eqFP611的发色团采用了显著不同的构象。共面的发色团构象及其直接环境为eqFP611的远红、高荧光性质提供了结构基础。eqFP611的结构扩展了我们对于绿色荧光蛋白家族密切相关成员中发色团可采用的构象范围的认识。
