| 摘要: |
| 膜蛋白是生物领域研究中的热点和难点。在光合作用研究中,对 于藻类个体发育过程中光合膜蛋白结构和功能的变化所知甚少,其中的一个限制因素是能否纯化得到大量高活性的稳定且均一的光合膜蛋白。作者从条斑紫菜 (Porphyra yezoensis)孢子体和配子体中分离纯化得到光合系统(PSⅡ)复合物,并研究了其完整性和放氧活性。结果表明,孢子体和配子体的PSⅡ复合物,在 4℃条件下保存比在-80℃下保存放氧活性高,稳定性高。配子体PSⅡ复合物,在-80℃保存第6天就已经没有放氧活性,而孢子体PSⅡ复合物仍有放氧活 性。对4℃下保存的PSII复合物进行分子筛柱层析,室温吸收光谱测定以及放氧活性测定,发现随着放氧活性逐渐降低,蛋白大分子有聚合现象。室温吸收光谱 表明经过长期的保存,吸收峰向短波长方向偏移,叶绿素易降解成为脱镁叶绿素。 |
| 关键词: 条斑紫菜(Porphyra yezoensis) 孢子体 配子体 光合系统(PSⅡ)稳定性 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(B33023019,Max-Planck-Gesellschaft) |
|
| Stability analysis of PSⅡ from gametophytes and sporophytes of Porphyra yezoensis |
|
|
| Abstract: |
| Little is known about the structural and functional alterations of photosystem membrane proteins during ontogenesis. One limitation of such studies is the availability of sufficient amounts of pure, stable and homogenous photosystem proteins with high activities. In this report, photosystem II was isolated from the sporophyte and gametophyte cells of the red alga Porphyra yezoensis. PSII activity assays were performed by measuring oxygen evolution during electron transfer from H2O to 1,4-benzoquinone, using an oxygen electrode(Hansatech). The isolated PSII complexes were stored at 4℃ and-80℃. The oxygen evolution activity was measured every other day. The results showed that PS II activity from both gametophytes and sporophytes decreased during storage. The oxygen evolution of PS II stored at 4℃ was higher than that stored at-80℃; At-80℃, Gametophyte PS II was completely inactive after 6 days while sporophyte PS II retained 50% of activity, nearly the same as when stored at 4 C. The PSII complexes stored at 4℃ were further analysed by gel filtration, oxygen evolution and absorption spectroscopy at room temperature. The gel filtration profiles showed that the protein complexes aggregated during storage. The chlorophyll absorption at 435 nm decreased, while the absorption at 417 nm increased. This implies that chlorophyll in PS II degraded to pheophytin. |
| Key words: Porphyra yezoensis sporophytes gametophytes PSII stability |
