Crystal structure of the C-terminal domain of the plant-specific microtubule-associated protein Spiral2
Crystal structure of the C-terminal domain of the plant-specific microtubule-associated protein Spiral2
复制标题
植物特异性微管相关蛋白 Spiral2 C 端结构域的晶体结构
DOI：
10.1107/s2053230x22011815
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Hayashi I.
中科院分区：
文献类型：
--
作者：
Ohno M.;Higuchi Y.;Hayashi I.
植物细胞在质膜下方形成微管阵列，称为“皮质微管”，这对于细胞壁组织和定向细胞生长至关重要。皮质微管独立于中心体成核。 Spiral2 是一种陆地植物特异性微管负端靶向蛋白，可通过抑制细丝的解聚来稳定负端。 Spiral2 拥有一个 N 端微管结合结构域和一个功能未知的保守 C 端结构域。本研究利用单波长反常色散法测定了 Spiral2 保守 C 端结构域的晶体结构。将模型细化至 2.2 Å 的分辨率，揭示了具有七个 α 螺旋的螺旋-转角-螺旋折叠。该蛋白质结晶为二聚体，但 SEC-MALS 分析显示该蛋白质是单体。结构同源性搜索表明该蛋白与剑素调节亚基 p80 的 C 端结构域相似。这里呈现的结构表明 Spiral2 的 C 末端结构域代表了整个王国的一类新型微管动力学调节剂。
Plant cells form microtubule arrays, called `cortical microtubules', beneath the plasma membrane which are critical for cell-wall organization and directional cell growth. Cortical microtubules are nucleated independently of centrosomes. Spiral2 is a land-plant-specific microtubule minus-end-targeting protein that stabilizes the minus ends by inhibiting depolymerization of the filament. Spiral2 possesses an N-terminal microtubule-binding domain and a conserved C-terminal domain whose function is unknown. In this study, the crystal structure of the conserved C-terminal domain of Spiral2 was determined using the single-wavelength anomalous dispersion method. Refinement of the model to a resolution of 2.2 Å revealed a helix–turn–helix fold with seven α-helices. The protein crystallized as a dimer, but SEC-MALS analysis showed the protein to be monomeric. A structural homology search revealed that the protein has similarity to the C-terminal domain of the katanin regulatory subunit p80. The structure presented here suggests that the C-terminal domain of Spiral2 represents a new class of microtubule dynamics modulator across the kingdom.