The structures of transcription factor CGL2947 from Corynebacterium glutamicum in two crystal forms:: A novel homodimer assembling and the implication for effector-binding mode
The structures of transcription factor CGL2947 from Corynebacterium glutamicum in two crystal forms:: A novel homodimer assembling and the implication for effector-binding mode
复制标题
DOI：
10.1110/ps.072976907
复制
发表时间：
2007-09-01
期刊：
影响因子：
8
通讯作者：
Tanaka, Isao
中科院分区：
文献类型：
--
作者：
Gao, Yong-Gui;Yao, Min;Tanaka, Isao
在转录因子中，由FadR、HutC、MocR、YtrA、AraR和PlmA亚家族组成的螺旋-转角-螺旋（HTH）GntR家族调节最多样的生物过程。通常，属于该家族的蛋白质含有N-末端DNA结合结构域和C-末端效应物结合/寡聚化结构域。YtrA亚家族的成员比该家族的其他成员短得多，具有120-130个残基的链长，其中约50个残基位于C-末端结构域中。由于这种长度，二聚化的模式和通过C-末端结构域结合效应物的能力令人困惑。在这里，我们首次报道了谷氨酸棒杆菌的转录因子CGL 2947的结构，它属于YtrA家族。该单体由一个DNA结合结构域组成，该结构域在N端含有一个有翼的HTH基序，在C端含有两个具有鱼钩形排列的螺旋（α 4和α 5）。两个单体的螺旋α 4和α 5相互交错在一起形成新的同二聚体组装体。定位了与2-甲基-2，4-戊二醇（MPD）对接的效应器调节口袋，并建议代表一种新的效应器结合模式。解决了两种晶体形式（MPD游离和结合在所提出的效应物结合口袋中）的结构。结构变化的影响，关于效应诱导的构象变化如何调节DNA的亲和力YtrA家族成员。
Among the transcription factors, the helix-turn-helix ( HTH) GntR family comprised of FadR, HutC, MocR, YtrA, AraR, and PlmA subfamilies regulates the most varied biological processes. Generally, proteins belonging to this family contain an N-terminal DNA-binding domain and a C-terminal effector-binding/oligomerization domain. The members of the YtrA subfamily are much shorter than other members of this family, with chain lengths of 120-130 residues with about 50 residues located in the C-terminal domain. Because of this length, the mode of dimerization and the ability to bind effectors by the C-terminal domain are puzzling. Here, we first report the structure of the transcription factor CGL2947 from Corynebacterium glutamicum, which belongs to the YtrA family. The monomer is composed of a DNA-binding domain containing a winged HTH motif in the N terminus and two helices ( alpha 4 and alpha 5) with a fishhook-shaped arrangement in the C terminus. Helices alpha 4 and alpha 5 of two monomers intertwine together to form a novel homodimer assembly. The effector-accommodating pocket with 2-methyl-2,4-pentanediol ( MPD) docked was located, and it was suggested to represent a novel mode of effector binding. The structures in two crystal forms ( MPD-free and -bound in the proposed effector-binding pocket) were solved. The structural variations have implications regarding how the effector-induced conformational change modulates DNA affinity for YtrA family members.