Magnesium chelatase (MgCh) is a heterotrimeric enzyme complex, composed of two AAA+ family subunits that can assembly into a double ring structure and a large catalytic subunit. The small AAA+ subunit has ATPase activity and can self-oligomerize into a ring structure, while the other AAA+ subunit lacks independent ATPase activity. Previous structural studies of the ATPase motor subunit of MgCh from a bacteriochlorophyll-synthesizing bacterium have identified a unique ATPase clade, but the model of oligomeric assembly is unclear. Here we present the hexameric structure of the MgCh ATPase motor subunit from the chlorophyll-synthesizing cyanobacterium Synechocystis sp. PCC 6803. This structure reveals details of how the hexameric ring is assembled, and thus provides a basis for further studying the heterotrimeric complex.

中文翻译：

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叶绿素生物合成中镁螯合酶ATPase电机亚基的六聚体结构。

镁螯合酶（MgCh）是一种异三聚体酶复合物，由两个AAA +家族亚基组成，可以组装成一个双环结构和一个大催化亚基。较小的AAA +亚基具有ATPase活性，并且可以自我寡聚成环结构，而其他AAA +亚基则缺乏独立的ATPase活性。先前对来自细菌叶绿素合成细菌的MgCh的ATPase电机亚基的结构研究已经确定了独特的ATPase进化枝，但寡聚组装的模型尚不清楚。在这里，我们介绍了从叶绿素合成的蓝藻Synechocystis sp。MgCh ATPase电机亚基的六聚体结构。PCC6803。这种结构揭示了六聚环如何组装的细节，因此为进一步研究异三聚体提供了基础。