Biochemical and structural study of Arabidopsis hexokinase 1
Biochemical and structural study of Arabidopsis hexokinase 1
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拟南芥己糖激酶1的生化和结构研究
DOI：
10.1107/s1399004714026091
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发表时间：
2015-02-01
期刊：
影响因子：
--
通讯作者：
Kuang, Tingyun
中科院分区：
文献类型：
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作者：
Feng, Juan;Zhao, Shun;Kuang, Tingyun
拟南芥己糖激酶1（AtHXK1）在糖酵解和糖传感中起着双重作用，参与重要的代谢和生理过程。葡萄糖代谢的葡萄糖信号的解偶联通过分析两个突变体（AtHXK1（G104D）和AtHXK1（S177A））来证明，这两个突变体是催化失活的，但在信号中仍然起作用。在这项研究中，底物结合实验表明，这两个催化失活的突变体具有高亲和力的葡萄糖，并已观察到野生型AtHXK1的有序底物结合机制。AtHXK1的结构在其非活性的unliganded形式和在其活性的葡萄糖结合的形式，分别在1.8和2.0埃的分辨率确定。这些结构揭示了葡萄糖结合后AtHXK1的结构域重排。葡萄糖结合形式的AtHXK1（S177A）的2.1埃分辨率结构显示出与野生型相似的葡萄糖结合相互作用。一个葡萄糖传感网络已经提出了基于这些结构。综上所述，这些结果为AtHXK1的双重功能提供了结构解释。
Hexokinase 1 from Arabidopsis thaliana (AtHXK1) plays a dual role in glycolysis and sugar sensing for vital metabolic and physiological processes. The uncoupling of glucose signalling from glucose metabolism was demonstrated by the analysis of two mutants (AtHXK1(G104D) and AtHXK1(S177A)) that are catalytically inactive but still functional in signalling. In this study, substrate-binding experiments indicate that the two catalytically inactive mutants have a high affinity for glucose, and an ordered substrate-binding mechanism has been observed for wild-type AtHXK1. The structure of AtHXK1 was determined both in its inactive unliganded form and in its active glucose-bound form at resolutions of 1.8 and 2.0 angstrom, respectively. These structures reveal a domain rearrangement of AtHXK1 upon glucose binding. The 2.1 angstrom resolution structure of AtHXK1(S177A) in the glucose-bound form shows similar glucose-binding interactions as the wild type. A glucose-sensing network has been proposed based on these structures. Taken together, the results provide a structural explanation for the dual functions of AtHXK1.