Crystallographic and functional studies of a plant temperature-induced lipocalin
Crystallographic and functional studies of a plant temperature-induced lipocalin
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DOI：
10.1016/j.bbagen.2023.130540
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发表时间：
2023-12-16
影响因子：
3
通讯作者：
Liu，Lin
中科院分区：
文献类型：
--
作者：
Dong，Chen-Song;Zhang，Wei-Lun;Liu，Lin
拟南芥温度诱导的脂质运载蛋白 (AtTIL) 是植物脂质运载蛋白的典型成员，参与多种细胞过程，特别是应激反应。生物信息和生理学研究提出了其混杂的配体结合能力，但其分子基础尚不清楚。在这里，我们报道了 AtTIL 与血红素复合物的 1.9-Å 晶体结构。血红素的分光光度吸光度滴定产生约 2 微摩尔的解离常数，表明 AtTIL 和血红素之间的相互作用相对较弱，AtTIL-血红素结构证实了这一点。尽管未检测到与视网膜或胆绿素的结合，但如与其他脂质运载蛋白结构的比较所表明的，不能排除这种可能性。这些结果表明AtTIL是细菌脂质运载蛋白Blc的结构和功能同系物。
Arabidopsis thalianatemperature-induced lipocalin (AtTIL) is a prototypical member of plant lipocalins and participates in a variety of cellular processes, particularly stress responses. Bioinformatical and physiological studies have proposed its promiscuous ligand-binding ability, but the molecular basis is yet unclear. Here, we report the 1.9-Å crystal structure ofAtTIL in complex with heme. Spectrophotometric absorbance titration with heme yields a dissociation constant of ∼2 micromolar, indicating the relatively weak interaction betweenAtTIL and heme, which is confirmed by theAtTIL-heme structure. Although binding to retinal or biliverdin is not detected, such possibility can not be precluded as suggested by comparison with other lipocalin structures. These results show thatAtTIL is a structural and functional homolog of the bacterial lipocalin Blc.