title: Structural basis for glycogen recognition by AMP-activated protein kinase.
abstract: AMP-activated protein kinase (AMPK) coordinates cellular metabolism in response to energy demand as well as to a variety of stimuli. The AMPK beta subunit acts as a scaffold for the alpha catalytic and gamma regulatory subunits and targets the AMPK heterotrimer to glycogen. We have determined the structure of the AMPK beta glycogen binding domain in complex with beta-cyclodextrin. The structure reveals a carbohydrate binding pocket that consolidates all known aspects of carbohydrate binding observed in starch binding domains into one site, with extensive contact between several residues and five glucose units. beta-cyclodextrin is held in a pincer-like grasp with two tryptophan residues cradling two beta-cyclodextrin glucose units and a leucine residue piercing the beta-cyclodextrin ring. Mutation of key beta-cyclodextrin binding residues either partially or completely prevents the glycogen binding domain from binding glycogen. Modeling suggests that this binding pocket enables AMPK to interact with glycogen anywhere across the carbohydrate's helical surface.
authors.affiliation: St. Vincent's Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia.
authors.forename: Galina
authors.initials: G
authors.lastname: Polekhina
authors.forename: Abhilasha
authors.initials: A
authors.lastname: Gupta
authors.forename: Bryce J W
authors.initials: BJ
authors.lastname: van Denderen
authors.forename: Susanne C
authors.initials: SC
authors.lastname: Feil
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Kemp
authors.forename: David
authors.initials: D
authors.lastname: Stapleton
authors.forename: Michael W
authors.initials: MW
authors.lastname: Parker
mesh_terms: D055372:AMP-Activated Protein Kinases; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002236:Carbohydrate Conformation; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005936:Glucans / Q000494:pharmacology; D005947:Glucose / Q000737:chemistry; D006003:Glycogen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007930:Leucine / Q000737:chemistry; D008099:Liver / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009844:Oligosaccharides / Q000494:pharmacology; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013059:Spectrum Analysis, Raman; D014364:Tryptophan / Q000737:chemistry; D014867:Water / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
chemical_list: D005936:Glucans; D009097:Multienzyme Complexes; D009844:Oligosaccharides; D021122:Protein Subunits; D047392:beta-Cyclodextrins; D014867:Water; C016549:maltohexaose; C031146:maltoheptaose; D014364:Tryptophan; D006003:Glycogen; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D007930:Leucine; D005947:Glucose; C031215:betadex