Mummadisetti Manjula P, Frankel Laurie K, Bellamy Henry D, Sallans Larry, Goettert Jost S, Brylinski Michal, Bricker Terry M
Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
The J. Bennett Johnston, Sr. Center for Advanced Microstructures & Devices, Louisiana State University , Baton Rouge, Louisiana 70806, United States.
Biochemistry. 2016 Jun 14;55(23):3204-13. doi: 10.1021/acs.biochem.6b00365. Epub 2016 Jun 3.
We have used protein cross-linking with the zero-length cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and radiolytic footprinting coupled with high-resolution tandem mass spectrometry, to examine the structure of higher-plant PsbO when it is bound to Photosystem II. Twenty intramolecular cross-linked residue pairs were identified. On the basis of this cross-linking data, spinach PsbO was modeled using the Thermosynechococcus vulcanus PsbO structure as a template, with the cross-linking distance constraints incorporated using the MODELLER program. Our model of higher-plant PsbO identifies several differences between the spinach and cyanobacterial proteins. The N-terminal region is particularly interesting, as this region has been suggested to be important for oxygen evolution and for the specific binding of PsbO to Photosystem II. Additionally, using radiolytic mapping, we have identified regions on spinach PsbO that are shielded from the bulk solvent. These domains may represent regions on PsbO that interact with other components, as yet unidentified, of the photosystem.
我们使用零长度交联剂1-乙基-3-(3-二甲基氨基丙基)碳二亚胺进行蛋白质交联，并结合高分辨率串联质谱进行辐射足迹分析，以研究高等植物的放氧增强蛋白（PsbO）与光系统II结合时的结构。我们鉴定出了20对分子内交联残基对。基于这些交联数据，以嗜热栖热放线菌的放氧增强蛋白（PsbO）结构为模板，利用MODELLER程序纳入交联距离限制条件，构建了菠菜放氧增强蛋白（PsbO）的模型。我们构建的高等植物放氧增强蛋白（PsbO）模型确定了菠菜蛋白与蓝细菌蛋白之间的几个差异。N端区域特别有趣，因为该区域被认为对氧气释放以及放氧增强蛋白（PsbO）与光系统II的特异性结合很重要。此外，通过辐射图谱分析，我们确定了菠菜放氧增强蛋白（PsbO）上与大量溶剂隔离的区域。这些结构域可能代表放氧增强蛋白（PsbO）上与光系统中其他尚未确定的成分相互作用的区域。
