Journal:Acta Cryst F:S2053230X21008542

Glycogen phosphorylase revisited: extending the resolution of the R- and T-state structures of the free enzyme and in complex with allosteric activators

Demetres D. Leonidas, Spyros E. Zographos, Katerina E. Tsitsanou, Vasiliki T. Skamnaki, George Stravodimos, and Efthimios Kyriakis ^[1]

Molecular Tour
The crystal structures of the free T- and R-state glycogen phosphorylase (GP) and the R-state GP in complex with allosteric activators IMP and AMP are reported, in improved resolution. GP is a validated pharmaceutical target for the development of antihyperglycaemic agents and the reported structures can have significant impact on structure-based drug design efforts. Comparisons to previously reported structures of lower resolution reveal the detailed conformation of important structural features of the allosteric transition from T- to R-state of GP.

The R-state rmGPb-AMP from a crystal grown in the presence of AMP:

• Each tetramer is colored in different colour
• Each subunit is colored in different colour, structurally equivalent subunits in the two tetramers are shown in the same colour

The different conformation of the N-terminal at the T and R state structures of GPb.

Animation of this scene.

PDB references: rabbit muscle glycogen phosphorylase, R-state, 3e3l; T-state, 7p7d; complex with AMP, R-state, 3e3n; complex with IMP, R-state, 3e3o.

References

1. ↑ Leonidas DD, Zographos SE, Tsitsanou KE, Skamnaki VT, Stravodimos G, Kyriakis E. Glycogen phosphorylase revisited: extending the resolution of the R- and T-state structures of the free enzyme and in complex with allosteric activators. Acta Crystallogr F Struct Biol Commun. 2021 Sep 1;77(Pt 9):303-311. doi:, 10.1107/S2053230X21008542. Epub 2021 Aug 26. PMID:34473107 doi:http://dx.doi.org/10.1107/S2053230X21008542