title: Architectural plasticity of AMPK revealed by electron microscopy and X-ray crystallography.
abstract: Mammalian AMP-activated protein kinase (AMPK) acts as an important sensor of cellular energy homeostasis related with AMP/ADP to ATP ratio. The overall architecture of AMPK has been determined in either homotrimer or monomer form by electron microscopy (EM) and X-ray crystallography successively. Accordingly proposed models have consistently revealed a key role of the α subunit linker in sensing adenosine nucleoside binding on the γ subunit and mediating allosteric regulation of kinase domain (KD) activity, whereas there are vital differences in orienting N-terminus of α subunit and locating carbohydrate-binding module (CBM) of β subunit. Given that Mg(2+), an indispensable cofactor of AMPK was present in the EM sample preparation buffer however absent when forming crystals, here we carried out further reconstructions without Mg(2+) to expectably inspect if this ion may contribute to this difference. However, no essential alteration has been found in this study compared to our early work. Further analyses indicate that the intra-molecular movement of the KD and CBM are most likely due to the flexible linkage of the disordered linkers with the rest portion as well as a contribution from the plasticity in the inter-molecular assembly mode, which might ulteriorly reveal an architectural complication of AMPK.
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ouyang
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yifang
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Guo
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Cheng
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wu
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000494:Allosteric Regulation; D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D008854:Microscopy, Electron; D008958:Models, Molecular; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D008024:Ligands; D021122:Protein Subunits; D011994:Recombinant Proteins; D055372:AMP-Activated Protein Kinases; D008274:Magnesium