Download MendeleyBinding of beta-d-glucopyranosyl bismethoxyphosphoramidate to glycogen phosphorylase b: kinetic and crystallographic studies
Chrysina, E.D., Kosmopoulou, M.N., Kardakaris, R., Bischler, N., Leonidas, D.D., Kannan, T., Loganathan, D., Oikonomakos, N.G.(2005) Bioorg Med Chem 13: 765-772
- PubMed: 15653344
- DOI: https://doi.org/10.1016/j.bmc.2004.10.040
- Primary Citation of Related Structures:
1XC7 - PubMed Abstract:
In an attempt to identify a new lead molecule that would enable the design of inhibitors with enhanced affinity for glycogen phosphorylase (GP), beta-D-glucopyranosyl bismethoxyphosphoramidate (phosphoramidate), a glucosyl phosphate analogue, was tested for inhibition of the enzyme. Kinetic experiments showed that the compound was a weak competitive inhibitor of rabbit muscle GPb (with respect to alpha-D-glucose-1-phosphate (Glc-1-P)) with a Ki value of 5.9 (+/-0.1) mM. In order to elucidate the structural basis of inhibition, we determined the structure of GPb complexed with the phosphoramidate at 1.83 A resolution. The complex structure reveals that the inhibitor binds at the catalytic site and induces significant conformational changes in the vicinity of this site. In particular, the 280s loop (residues 282-287) shifts 0.4-4.3 A (main-chain atoms) to accommodate the phosphoramidate, but these conformational changes do not lead to increased contacts between the inhibitor and the protein that would improve ligand binding.
Organizational Affiliation:
Institute of Organic and Pharmaceutical Chemistry, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens, Greece.
