The allosteric transition of glycogen phosphorylase.
The crystal structure of R-state glycogen phosphorylase b has been determined at 2.9 A resolution. A comparison of T-state and R-state structures of the enzyme explains its cooperative behaviour on ligand binding and the allosteric regulation of its activity. Communication between catalytic sites of the dimer is provided by a change in packing geometry of two helices linking each site with the subunit interface. Activation by AMP or by phosphorylation results in a quaternary conformational change that switches these two helices into the R-state conformation.
Barford
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Laboratory of Molecular Biophysics, University of Oxford, UK.
Johnson
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D000494:Allosteric Regulation; D000818:Animals; D001665:Binding Sites; D002384:Catalysis; D003198:Computer Simulation; D006860:Hydrogen Bonding; D009132:Muscles / Q000201:enzymology; D006005:Phosphorylases / Q000502:physiology*; D011487:Protein Conformation; D011817:Rabbits; D013329:Structure-Activity Relationship
D006005:Phosphorylases