3e3n
The Glycogen phosphorylase b R state- AMP complex
Structural highlights
FunctionPYGM_RABIT Phosphorylase is an important allosteric enzyme in carbohydrate metabolism. Enzymes from different sources differ in their regulatory mechanisms and in their natural substrates. However, all known phosphorylases share catalytic and structural properties. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structures of free T-state and R-state glycogen phosphorylase (GP) and of R-state GP in complex with the allosteric activators IMP and AMP are reported at improved resolution. GP is a validated pharmaceutical target for the development of antihyperglycaemic agents, and the reported structures may have a significant impact on structure-based drug-design efforts. Comparisons with previously reported structures at lower resolution reveal the detailed conformation of important structural features in the allosteric transition of GP from the T-state to the R-state. The conformation of the N-terminal segment (residues 7-17), the position of which was not located in previous T-state structures, was revealed to form an alpha-helix (now termed alpha0). The conformation of this segment (which contains Ser14, phosphorylation of which leads to the activation of GP) is significantly different between the T-state and the R-state, pointing in opposite directions. In the T-state it is packed between helices alpha4 and alpha16 (residues 104-115 and 497-508, respectively), while in the R-state it is packed against helix alpha1 (residues 22'-38') and towards the loop connecting helices alpha4' and alpha5' of the neighbouring subunit. The allosteric binding site where AMP and IMP bind is formed by the ordering of a loop (residues 313-326) which is disordered in the free structure, and adopts a conformation dictated mainly by the type of nucleotide that binds at this site. Glycogen phosphorylase revisited: extending the resolution of the R- and T-state structures of the free enzyme and in complex with allosteric activators.,Leonidas DD, Zographos SE, Tsitsanou KE, Skamnaki VT, Stravodimos G, Kyriakis E Acta Crystallogr F Struct Biol Commun. 2021 Sep 1;77(Pt 9):303-311. doi:, 10.1107/S2053230X21008542. Epub 2021 Aug 26. PMID:34473107[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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