兔C反应蛋白的二维结晶研究(英文)

Electron microscopic study on two dimensional crystallization of rabbit C reactive protein subunits

兔C反应蛋白 (CRP)由 5个单体组成 ,是一种典型的急性期蛋白。使用从天然CRP储存液中分离出的、由自然解聚生成的CRP单体 ,我们在由eggPC、lysoPC和DMPS组成的负电磷脂膜上得到了两种单体晶体。其中的一种MI先前已由本实验室获得 ,而另一种MII则是首次发现。进一步的电子晶体学分析表明 ,MII晶体的晶格参数为 :a =2 0 6 (± 0 1 )nm、b =1 6 1(± 0 1 )nm和γ =90 (± 1 )°,其投影图的分辨率为 2 0 6nm ,并具有P2对称性。通过比较两种晶体的排列方式和形成类型 。

C reactive protein (CRP), one of the most characteristic acute phase proteins, is composed of five identical non covalently linked monomers.In current work, using CRP subunits isolated from CRP stock by size exclusion chromatography, two types of two dimensional (2D) monomeric crystals were obtained on negatively charged lipid monolayers composed of egg PC, lysoPC and DMPS.One (MI) is as reported previously and the other one (MII) is discovered for the first time.Electron crystallographic analysis of MII crystal shows a lattice with parameters of a =20 6(±0 1) nm, b =16 1(±0 1) nm and γ = 90(±1)°, and the projection map with P2 symmetry is produced at the resolution of 2 06 nm.The comparison of the packing styles and formation conditions of the two types of crystals indicates that the separated CRP subunits may be the major form of modified CRP previously reported.