IM30, the inner membrane-associated protein of 30 kDa, is conserved in cyanobacteria and chloroplasts. Although its exact physiological function is still mysterious, IM30 is clearly essential for thylakoid membrane biogenesis and/or dynamics. Recently, a cryptic IM30 GTPase activity has been reported, albeit thus far no physiological function has been attributed to this. Yet, it is still possible that GTP binding/hydrolysis affects formation of the prototypical large homo-oligomeric IM30 ring and rod structures. Here, we show that the Synechocystis sp. PCC 6803 IM30 protein in fact is an NTPase that hydrolyzes GTP and ATP, but not CTP or UTP, with about identical rates. While IM30 forms large oligomeric ring complexes, nucleotide binding and/or hydrolysis are clearly not required for ring formation.

中文翻译：

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IM30 环的形成不需要基于嘌呤的核苷酸的结合和/或水解

IM30 是 30 kDa 的内膜相关蛋白，在蓝细菌和叶绿体中是保守的。尽管其确切的生理功能仍然是个谜，但 IM30 显然对类囊体膜的生物发生和/或动力学至关重要。最近，已经报道了一种神秘的 IM30 GTPase 活性，尽管到目前为止还没有将其归因于生理功能。然而，GTP 结合/水解仍然可能影响原型大同寡聚 IM30 环和杆结构的形成。在这里，我们展示了Synechocystis sp。PCC 6803 IM30 蛋白实际上是一种 NTP 酶，以大致相同的速率水解 GTP 和 ATP，但不水解 CTP 或 UTP。虽然 IM30 形成大的寡聚环复合物，但环形成显然不需要核苷酸结合和/或水解。