发菜藻胆体亚单位的分子排布

Arrangements of subunits of phycobilisomes from Nostoc flagelliforme

本文通过负染电镜技术和单颗粒分析的方法首次对发菜藻胆体进行了深入研究。电镜结果显示,发菜藻胆体呈典型的半圆盘形,包括三个核柱体和六个杆状结构。藻胆体的三维结构显示藻胆体核柱体的顶面呈边长为10nm的三角形,三个柱体通过一个共同的顶点以三次轴对称地连接到一起;藻胆体的杆与核柱体的连接也是通过核柱体的顶点完成的。结合别藻蓝蛋白的晶体结构,并考察藻胆素在别藻蓝蛋白上的分布,我们认为这种顶点的连接方式有利于光能高效地从杆传递到核,进而传递到类囊体膜。

In this work the phycobilisomes from Nostoc flagelliforme were first carefully studied by electron microscopy and single particle analysis. The 3D structure showed that the top view of allophycocyanins cylinder of phycobilisome has a shape of triangle with a sidelength of 10nm; three allophycocyanins cylinders organized together at a common vertex by 3-fold axis. Further, the rods of phycobilisome linked the cylinder by similar vertex style. Considering the distribution of phycocyanobilins on the allophycocyanins, we proposed that α84 CYS phycocyanobilins play a key role in the energy transfer process from rods to cylinder, and to the thylakoid membrane.