4qs7 | pdb_00004qs7
Arabidopsis Hexokinase 1 (AtHXK1) structure in glucose-bound form
Structural highlights
Function[HXK1_ARATH] Fructose and glucose phosphorylating enzyme. May be involved in the phosphorylation of glucose during the export from mitochondrion to cytosol. Acts as sugar sensor which may regulate sugar-dependent gene repression or activation. Mediates the effects of sugar on plant growth and development independently of its catalytic activity or the sugar metabolism. May regulate the execution of program cell death in plant cells.[1] [2] [3] Publication Abstract from PubMedHexokinase 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 A, respectively. These structures reveal a domain rearrangement of AtHXK1 upon glucose binding. The 2.1 A 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. Biochemical and structural study of Arabidopsis hexokinase 1.,Feng J, Zhao S, Chen X, Wang W, Dong W, Chen J, Shen JR, Liu L, Kuang T Acta Crystallogr D Biol Crystallogr. 2015 Feb;71(Pt 2):367-75. doi:, 10.1107/S1399004714026091. Epub 2015 Jan 23. PMID:25664748[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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