Conformational analysis of the blue-light sensing protein YtvA reveals a competitive interface for LOV-LOV dimerization and interdomain interactions
Conformational analysis of the blue-light sensing protein YtvA reveals a competitive interface for LOV-LOV dimerization and interdomain interactions
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DOI：
10.1039/b610375h
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发表时间：
2007-01-01
影响因子：
3.1
通讯作者：
Gaertner, Wolfgang
中科院分区：
文献类型：
--
作者：
Buttani, Valentina;Losi, Aba;Gaertner, Wolfgang
枯草芽孢杆菌蛋白YtvA与植物向光蛋白相关，因为它通过连接到核苷酸结合STAS结构域的黄素结合LOV结构域来感测UVA蓝光。结构域间相互作用和功能调节的结构基础尚不清楚。在这里，我们报告的构象分析的三个YtvA结构，通过尺寸排阻色谱，圆二色性（CD）和分子对接模拟。分离的YtvA-LOV结构域（YLOV，aa 25-126）具有在全长YtvA中阻止的二聚化的强烈倾向，但在携带N-末端延伸的YLOV（N-YLOV，aa 1-126）中仍然观察到。CD数据的分析表明，N-末端帽和LOV与STAS结构域之间的接头区（aa 127-147）都是螺旋形的，并且中心β-支架在LOV结构域二聚体中变形。中心β-支架参与二聚化得到了YLOV二聚体对接模拟的支持，并且该区域的重要性通过CD数据分析中出现的光诱导构象变化突出显示。在YtvA中，β-链部分明显较少扭曲，并且检测到环/转角部分的明显光驱动变化。这些数据揭示了LOV-LOV和蛋白质内相互作用的共同表面，涉及中央β-支架，并为研究LOV蛋白中光激活和调节的分子基础提供了线索。
The Bacillus subtilis protein YtvA is related to plant phototropins in that it senses UVA-blue-light by means of the flavin binding LOV domain, linked to a nucleotide-binding STAS domain. The structural basis for interdomain interactions and functional regulation are not known. Here we report the conformational analysis of three YtvA constructs, by means of size exclusion chromatography, circular dichroism (CD) and molecular docking simulations. The isolated YtvA-LOV domain (YLOV, aa 25-126) has a strong tendency to dimerize, prevented in full-length YtvA, but still observed in YLOV carrying the N-terminal extension (N-YLOV, aa 1-126). The analysis of CD data shows that both the N-terminal cap and the linker region (aa 127-147) between the LOV and the STAS domain are helical and that the central beta-scaffold is distorted in the LOV domains dimers. The involvement of the central beta-scaffold in dimerization is supported by docking simulation of the YLOV dimer and the importance of this region is highlighted by light-induced conformational changes, emerging from the CD data analysis. In YtvA, the beta-strand fraction is notably less distorted and distinct light-driven changes in the loops/turn fraction are detected. The data uncover a common surface for LOV-LOV and intraprotein interaction, involving the central beta-scaffold, and offer hints to investigate the molecular basis of light-activation and regulation in LOV proteins.