Structural basis for glycogen recognition by AMP-activated protein kinase.
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.
Polekhina
Galina
G
St. Vincent's Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia.
Gupta
Abhilasha
A
van Denderen
Bryce J W
BJ
Feil
Susanne C
SC
Kemp
Bruce E
BE
Stapleton
David
D
Parker
Michael W
MW
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
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