Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Biol Chem. 2011 Aug;392(8-9):791-7. doi: 10.1515/BC.2011.082.
Septins constitute a family of conserved guanine nucleotide binding proteins found in a wide range of organisms from fungi to mammals. Members of the family share a canonical G-domain with N- and C-terminal extensions. G-domains assemble into hetero-oligomeric complexes which form non-polarised filaments or rings. Linear filaments are formed between the G-domains using either the guanine nucleotide binding site (G interface) or N- and C-terminal extensions (NC interface). Sept7 is a unique among the 13 human septins in that it occupies the ends of hexameric building blocks which assemble into non-polarised filaments. To gain insight into its particular properties we performed structural and biochemical studies on Sept7. We solved the crystal structure of a Sept7 dimer in the GDP-bound state. The structure and biochemistry of Sept7 provide new insights into the dynamics of the G interface and outline the differences in the properties of Sept7 compared to the members of group 2 septins.
七聚体是一类保守的鸟嘌呤核苷酸结合蛋白家族，存在于从真菌到哺乳动物等多种生物中。该家族的成员具有典型的 G 结构域和 N 端及 C 端的延伸。G 结构域组装成异源寡聚复合物，形成非极性的丝状或环状结构。线性丝状结构通过 G 结构域的鸟嘌呤核苷酸结合位点（G 界面）或 N 端和 C 端延伸（NC 界面）形成。在 13 种人类七聚体中，Sept7 是独一无二的，因为它占据了六聚体构建块的末端，这些构建块组装成非极性丝状结构。为了深入了解其特殊性质，我们对 Sept7 进行了结构和生化研究。我们解析了 GDP 结合状态下 Sept7 二聚体的晶体结构。该结构和生化研究为 G 界面的动力学提供了新的见解，并概述了 Sept7 与 2 组七聚体成员之间性质的差异。
