光照条件变化对蓝隐藻色素蛋白复合物表达含量的影响

Effects of Light Illumination Variation on Expression of Pigment-rotein Complexin Chroomonas placoidea

前期研究发现蓝隐藻(Chroomonas placoidea)藻蓝蛋白PC645存在未报道过的β亚基,但其受光照条件的影响及表达情况不明。实验比较了6组不同光照条件下培养的蓝隐藻对数生长期细胞的色素组成变化及PC645亚基的表达差异。发现光照增加对叶绿素a/c-蛋白复合物影响不明显,但有利于PC645的积累;且影响PC645中两种β亚基的相对表达量,而对α亚基含量影响很小。1级12 h和24 h时β_(2)亚基相对含量最高,较低或过高强度的光照都不利于β_(2)的表达。说明PC645在蓝隐藻光适应机制中可能担负调节作用,β_(2)亚基的存在不仅影响隐藻藻胆蛋白的聚合形式,也与藻细胞的光能传递功能可调性相关。实验结果将为分析新亚基的功能,阐明隐藻特异的光合系统结构与机理提供依据。

An unreportedβsubunit is found in phycocyanin PC645 of Chroomonas placoidea in our previous works.However,the expression and photo-adaptive function of this subunit under different illumination conditions are un-known.In this study,the changes of pigment composition and expression of PC645 subunits in logarithmic growth cells of C.placoidea cultured under six levels of different light culture conditions are compared.The results show that the increasing of light intensity has no significant effects on Chl a/c-light-harvesting complex,while,facilitates to the accumulation of PC645.Illumination variation particularly affects the relative contents of the twoβsubunits of PC645 but doesn't affect that of theαsubunit.Theβ_(2) subunit exhibits the highest relative content at level 112 h and 24 h.Too low or high intensity of light are both not conducive to the expression ofβ_(2) subunit.These results suggest that PC645 may play an important role of regulation in light adaptation mechanism of C.placoidea.The ex-isting of subunitβ_(2)affects not only the aggregation of cryptophytic phycobiliproteins,but also the adjustability of en-ergy transfer in algal cell.The experimental results will provide a basis for analyzing the function of the new subunit and elucidating the novel photosynthetic system structure and mechanism of cryptophyts.