一种水华蓝藻气囊的分离纯化及气囊结构蛋白的鉴定

Isolation and structural proteins determination of gas vesicles from a bloom-forming cyanobacterium

摘要:

【目的】从水华蓝藻铜绿微囊藻(Microcystis aeruginosa PCC 7806)的细胞中分离纯化出高纯度且完整的气囊，并对气囊的结构组成蛋白进行鉴定。【方法】采用渗透冲击与溶菌酶处理相结合的方法，进行多次低速离心提纯气囊，纯化所得气囊用负染色透射电镜观察气囊的纯度、完整度和形态。将纯化得到的气囊溶解后进行SDS-PAGE电泳，电泳后的蛋白条带运用LC-MS质谱法完成鉴定。【结果】从气囊的电镜照片可以看出提纯后的气囊纯度高，完整性好。气囊是两端呈锥状的圆柱体状，各气囊的直径大小一致，约120 nm，但长度不同，从约500 nm到1 500 nm不等。SDS-PAGE电泳和质谱法鉴定出气囊的两种主要结构组成蛋白GvpA和GvpC。【结论】这些研究对后续揭示气囊的精细结构和深入研究水华蓝藻浮力调节机制具有重要的意义。

Abstract:

[Objective] In order to isolate high-purity and intact gas vesicles from the cells of bloom-forming cyanobacterium Microcystis aeruginosa PCC 7806, and to identify structural proteins of gas vesicles. [Methods] Osmotic shock combined with lysozyme treatment and low speed centrifugation were used to isolate and purify gas vesicles. The purity, integrity and characteristic shape of gas vesicles were examined by negative staining and transmission electron microscope. The structural proteins of gas vesicles were detected and identified by SDS-PAGE electrophoresis and LC-MS. [Results] Electron microscopic examination indicated that the isolated gas vesicles had high purity and showed good integrity. They took a cylinder shape with conical end caps and had a similar diameter of about 120 nm and the variable lengths from 500 to 1 500 nm. GvpA and GvpC identified by SDS-PAGE electrophoresis and LC-MS were two main structural proteins of gas vesicles. [Conclusion] Our findings would have great significance to reveal the fine structure of gas vesicles and to further study the buoyancy regulation mechanism of bloom-forming cyanobacteria.