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B6db references: 21617019

type Journal Article
authors Oikonomakos, N. G.; Skamnaki, V. T.; Osz, E.; Szilagyi, L.; Somsak, L.; Docsa, T.; Toth, B.; Gergely, P.
title Kinetic and crystallographic studies of glucopyranosylidene spirothiohydantoin binding to glycogen phosphorylase B
journal Bioorg Med Chem
ui 21617019
year (2002)
volume 10
number 2
pages 261-8.
keywords Animal
abstract Glucopyranosylidene spirothiohydantoin (TH) has been identified as a potential inhibitor of both muscle and liver glycogen phosphorylase b (GPb) and a (GPa) and shown to diminish liver GPa activity in vitro. Kinetic experiments reported here show that TH inhibits muscle GPb competitively with respect to both substrates phosphate (K(i)=2.3 microM) and glycogen (K(i)=2.8 microM). The structure of the GPb-TH complex has been determined at a resolution of 2.26 A and refined to a crystallographic R value of 0.193 (R(free)=0.211). The structure of GPb- TH complex reveals that the inhibitor can be accommodated in the catalytic site of T-state GPb with very little change of the tertiary structure, and provides a basis of understanding potency and specificity of the inhibitor. The glucopyranose moiety makes the standard hydrogen bonds and van der Waals contacts as observed in the glucose complex, while the rigid thiohydantoin group is in a favourable electrostatic environment and makes additional polar contacts to the protein.
last changed 2002/11/12 16:17

B6db references