Nanomolar Inhibitors of Glycogen Phosphorylase Based on β-<scp>d</scp>-Glucosaminyl Heterocycles: A Combined Synthetic, Enzyme Kinetic, and Protein Crystallography Study

Bokor, Éva; Kyriakis, E.; Solovou, T.G.A.; Koppány, Csenge; Kantsadi, A.L.; Szabó, Katalin; Szakács, Andrea; Stravodimos, G.A.; Docsa, Tibor; Skamnaki, Vassiliki T.; Zographos, S.E.; Gergely, Pál; Leonidas, D.D.; Somsák, László

doi:10.1021/acs.jmedchem.7b01056

Cited by 19 publications

(25 citation statements)

References 73 publications

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“…RmGP and hlGP share 97% sequence homology and both enzymes are fully conserved in sequence and structure at the active site; thus, any structural analysis of rmGPb is applicable to hlGP. This has been demonstrated in several inhibitor studies (Kantsadi et al, 2016(Kantsadi et al, , 2017Bokor et al, 2017;Kyriakis et al, 2018Kyriakis et al, , 2020Chetter et al, 2020;Fischer et al, 2019). In the last 30 years many inhibitor studies have been reported which have led to the discovery of potent and specific GP inhibitors (Oikonomakos, 2002;Somsá k et al, 2008;Somsá k, 2011;Stravodimos et al, 2017;Hayes et al, 2014).…”

Section: Introductionmentioning

confidence: 90%

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

et al. 2021

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The 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 α-helix (now termed α0). 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 α4 and α16 (residues 104–115 and 497–508, respectively), while in the R-state it is packed against helix α1 (residues 22′–38′) and towards the loop connecting helices α4′ and α5′ 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.

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Section: Introductionmentioning

confidence: 90%

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

et al. 2021

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“…As already mentioned, the amino acid sequence homology among the three GP isoforms (brain, liver, and muscle) is very high (≈80%) [ 7 ]. Additionally, the catalytic site is identically conserved in all mammalian GPs, with almost 100% homology for this site, indicating that compounds inhibiting mammalian muscle GP at this site are also able to inhibit human liver GP [ 10 , 30 ]. Thus, in order to use an easily available and low-cost enzyme, avoiding long isolation and purification procedures, the commercial rabbit muscle isoform GP was selected to implement the method.…”

Section: Discussionmentioning

confidence: 99%

Optimization and Validation of an In Vitro Standardized Glycogen Phosphorylase Activity Assay

et al. 2021

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Glycogen phosphorylase (GP) is a key enzyme in the glycogenolysis pathway and a potential therapeutic target in the management of type 2 diabetes. It catalyzes a reversible reaction: the release of the terminal glucosyl residue from glycogen as glucose 1-phosphate; or the transfer of glucose from glucose 1-phosphate to glycogen. A colorimetric method to follow in vitro the activity of GP with usefulness in structure-activity relationship studies and high-throughput screening capability is herein described. The obtained results allowed the choice of the optimal concentration of enzyme of 0.38 U/mL, 0.25 mM glucose 1-phosphate, 0.25 mg/mL glycogen, and temperature of 37 °C. Three known GP inhibitors, CP-91149, a synthetic inhibitor, caffeine, an alkaloid, and ellagic acid, a polyphenol, were used to validate the method, CP-91149 being the most active inhibitor. The effect of glucose on the IC50 value of CP-91149 was also investigated, which decreased when the concentration of glucose increased. The assay parameters for a high-throughput screening method for discovery of new potential GP inhibitors were optimized and standardized, which is desirable for the reproducibility and comparison of results in the literature. The optimized method can be applied to the study of a panel of synthetic and/or natural compounds, such as polyphenols.

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“…Introduction of a double bond into the glucopyranose ring as in 59-61, to make the compounds somewhat similar to the glycosyliumion-like transition state of the catalyzed reaction, resulted in inefficient derivatives [84]. However, the exchange of the 2-OH to the isosteric NH 2 group gave highly active compounds 62-64, nevertheless, these lagged behind the parent glucose derivatives by factors of ~22, ~12 and ~6, respectively [85]. These compounds represent the first strongly binding GPIs with modified glucose moieties that can be advantageous from the point of view of selectivity in applications.…”

Section: Inhibition Of Rmgpb By Compounds Modified In the Glucose Unitmentioning

confidence: 99%

New syntheses towards C-glycosyl type glycomimetics

Somsák

Bokor

Juhász

et al. 2019

Pure and Applied Chemistry

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Glycomimetics are compounds that resemble carbohydrate molecules in their chemical structure and/or biological effect. A large variety of compounds can be designed and synthesized to get glycomimetics, however, C-glycosyl derivatives represent one of the most frequently studied subgroup. In the present survey syntheses of a range of five- and six membered C-glycopyranosyl heterocycles, anhydro-aldimine type compounds, exo-glycals, C-glycosyl styrenes, carbon-sulfur bonded oligosaccharide mimics are described. Some of the C-glycopyranosyl azoles, namely 1,2,4-triazoles and imidazoles belong to the most efficient glucose analog inhibitors of glycogen phosphorylase known to date. Biological studies revealed the therapeutical potential of such inhibitors. Other synthetic derivatives offer versatile possibilities to get further glycomimetics.

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Nanomolar Inhibitors of Glycogen Phosphorylase Based on β-d-Glucosaminyl Heterocycles: A Combined Synthetic, Enzyme Kinetic, and Protein Crystallography Study

Cited by 19 publications

References 73 publications

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

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

Optimization and Validation of an In Vitro Standardized Glycogen Phosphorylase Activity Assay

New syntheses towards C-glycosyl type glycomimetics

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