Zent Eldar, Wittinghofer Alfred
Biol Chem. 2014 Feb;395(2):169-80. doi: 10.1515/hsz-2013-0268.
Septins form oligomeric complexes consisting of septins from different subgroups, which form filaments that are involved in a number of biological processes. They are GTP-binding proteins that contain all the necessary elements to perform the general GDP-to-GTP conformational switch. It is however unclear whether or not such a switch is important for the dynamics of septin filaments. Here we investigate the complex GTPase reaction of members of each of the four human septin groups, which is dominated by the stability of dimer formation via the nucleotide binding or so-called G-interface. The results also show that the actual hydrolysis reaction is very similar for three septin groups in the monomeric state while the Sept6 has no GTPase activity. Sept7, the only member of the Sept7 subgroup, forms a very tight G-interface dimer in the GDP-bound state. Here we show that the stability of the interface is dramatically decreased by exchanging GDP with a nucleoside triphosphate, which is believed to influence filament formation and dynamics via Sept7.
Septins形成由来自不同亚组的Septins组成的寡聚复合物，这些复合物形成参与许多生物过程的细丝。它们是GTP结合蛋白，包含执行一般GDP到GTP构象转换所需的所有必要元件。然而，尚不清楚这种转换对于septin细丝的动态是否重要。在这里，我们研究了四个人类septin组中每个成员的复杂GTPase反应，该反应由通过核苷酸结合或所谓的G界面形成二聚体的稳定性主导。结果还表明，在单体状态下，三个septin组的实际水解反应非常相似，而Sept6没有GTPase活性。Sept7是Sept7亚组的唯一成员，在GDP结合状态下形成非常紧密的G界面二聚体。在这里，我们表明，通过用核苷三磷酸交换GDP，界面的稳定性会显著降低，这被认为会通过Sept7影响细丝的形成和动态。
