N-acetyl-beta-D-glucopyranosylamine: a potent T-state inhibitor of glycogen phosphorylase. A comparison with alpha-D-glucose.Oikonomakos, N.G., Kontou, M., Zographos, S.E., Watson, K.A., Johnson, L.N., Bichard, C.J., Fleet, G.W., Acharya, K.R.
(1995) Protein Sci. 4: 2469-2477
- PubMed: 8580837
- DOI: 10.1002/pro.5560041203
- Also Cited By: 1WW3, 1WW2
- PubMed Abstract:
- The Design of Inhibitors of Glycogen Phosphorylase: A Study of Alpha and Beta Glucoheptonamides and 1-Thio-Beta-D-Glucose Compounds
Watson, K.A.,Mitchell, E.P.,Johnson, L.N.,Son, J.C.,Bichard, C.J.F.,Orchard, M.G.,Fleet, G.W.J.,Oikonomakos, N.G.,Leonidas, D.D.,Kontou, M.,Papageorgiou, A.C.
(1994) Biochemistry 33: 5745
Structure-based drug design has led to the discovery of a number of glucose analogue inhibitors of glycogen phosphorylase that have an increased affinity compared to alpha-D-glucose (Ki = 1.7 mM). The best inhibitor in the class of N-acyl derivatives ...
Structure-based drug design has led to the discovery of a number of glucose analogue inhibitors of glycogen phosphorylase that have an increased affinity compared to alpha-D-glucose (Ki = 1.7 mM). The best inhibitor in the class of N-acyl derivatives of beta-D-glucopyranosylamine, N-acetyl-beta-D-glucopyranosylamine (1-GlcNAc), has been characterized by kinetic, ultracentrifugation, and crystallographic studies. 1-GlcNAc acts as a competitive inhibitor for both the b (Ki = 32 microM) and the a (Ki = 35 microM) forms of the enzyme with respect to glucose 1-phosphate and in synergism with caffeine, mimicking the binding of glucose. Sedimentation velocity experiments demonstrated that 1-GlcNAc was able to induce dissociation of tetrameric phosphorylase a and stabilization of the dimeric T-state conformation. Co-crystals of the phosphorylase b-1-GlcNAc-IMP complex were grown in space group P4(3)2(1)2, with native-like unit cell dimensions, and the complex structure has been refined to give a crystallographic R factor of 18.1%, for data between 8 and 2.3 A resolution. 1-GlcNAc binds tightly at the catalytic site of T-state phosphorylase b at approximately the same position as that of alpha-D-glucose. The ligand can be accommodated in the catalytic site with very little change in the protein structure and stabilizes the T-state conformation of the 280s loop by making several favorable contacts to Asn 284 of this loop. Structural comparisons show that the T-state phosphorylase b-1-GlcNAc-IMP complex structure is overall similar to the T-state phosphorylase b-alpha-D-glucose complex structure. The structure of the 1-GlcNAc complex provides a rational for the biochemical properties of the inhibitor.
Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece. email@example.com