title: Biochemical and structural study of Arabidopsis hexokinase 1.
abstract: 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 Å, respectively. These structures reveal a domain rearrangement of AtHXK1 upon glucose binding. The 2.1 Å 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.
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Juan
authors: J
authors: Feng
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Shun
authors: S
authors: Zhao
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Xuemin
authors: X
authors: Chen
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Wenda
authors: W
authors: Wang
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Wei
authors: W
authors: Dong
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Jinghua
authors: J
authors: Chen
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Jian-Ren
authors: JR
authors: Shen
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Lin
authors: L
authors: Liu
authors: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China.
authors: Tingyun
authors: T
authors: Kuang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017360:Arabidopsis / Q000737:chemistry* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D005947:Glucose / Q000378:metabolism; D006593:Hexokinase / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D029681:Arabidopsis Proteins; D000255:Adenosine Triphosphate; D006593:Hexokinase; C473630:ATHXK1 protein, Arabidopsis; D005947:Glucose
keywords: domain reorientation; hexokinase; sugar sensor