| 1. |
- Bach, Anders, et al.
(författare)
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A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:9, s. 3317-3322
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-D-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors are lacking. Here we report the design and synthesis of a novel dimeric inhibitor, Tat-NPEG4(IETDV)(2) (Tat-N-dimer), which binds the tandem PDZ1-2 domain of PSD-95 with an unprecedented high affinity of 4.6 nM, and displays extensive protease-resistance as evaluated in vitro by stability-measurements in human blood plasma. X-ray crystallography, NMR, and small-angle X-ray scattering (SAXS) deduced a true bivalent interaction between dimeric inhibitor and PDZ1-2, and also provided a dynamic model of the conformational changes of PDZ1-2 induced by the dimeric inhibitor. A single intravenous injection of Tat-N-dimer (3 nmol/g) to mice subjected to focal cerebral ischemia reduces infarct volume with 40% and restores motor functions. Thus, Tat-N-dimer is a highly efficacious neuroprotective agent with therapeutic potential in stroke.
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| 2. |
- Backe, Marie Balslev, et al.
(författare)
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Lysine demethylase inhibition protects pancreatic β cells from apoptosis and improves β-cell function
- 2018
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207. ; 460, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- Transcriptional changes control β-cell survival in response to inflammatory stress. Posttranslational modifications of histone and non-histone transcriptional regulators activate or repress gene transcription, but the link to cell-fate signaling is unclear. Inhibition of lysine deacetylases (KDACs) protects β cells from cytokine-induced apoptosis and reduces type 1 diabetes incidence in animals. We hypothesized that also lysine demethylases (KDMs) regulate β-cell fate in response to inflammatory stress.Expression of the demethylase Kdm6B was upregulated by proinflammatory cytokines suggesting a possible role in inflammation-induced β-cell destruction. Inhibition of KDM6 demethylases using the selective inhibitor GSK-J4 protected insulin-producing cells and human and mouse islets from cytokine-induced apoptosis by blunting nuclear factor (NF)-κB signaling and endoplasmic reticulum (ER) stress response gene expression. GSK-J4 furthermore increased expression of insulin gene and glucose-stimulated insulin secretion. Expression of genes regulating purinergic and cytokine ligand-receptor interactions was downregulated following GSK-J4 exposure, while expression of genes involved in cell maintenance and survival was upregulated. These data suggest that KDMs are important regulators of inflammation-induced β-cell dysfunction and death.
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| 3. |
- Krintel, Christian, et al.
(författare)
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Binding of a negative allosteric modulator and competitive antagonist can occur simultaneously at the ionotropic glutamate receptor GluA2
- 2021
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:3, s. 995-1007
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Tidskriftsartikel (refereegranskat)abstract
- Ionotropic glutamate receptors are ligand-gated ion channels governing neurotransmission in the central nervous system. Three major types of antagonists are known for the AMPA-type receptor GluA2: competitive, non-competitive (i.e. negative allosteric modulators; NAMs) used for treatment of epilepsy, and uncompetitive antagonists. We here report a 4.65 Å resolution X-ray structure of GluA2, revealing that four molecules of the competitive antagonist ZK200775 and four molecules of the NAM GYKI53655 are capable of binding at the same time. Using negative stain electron microscopy, we show that GYKI53655 alone or ZK200775/GYKI53655 in combination predominantly result in compact receptor forms. The agonist AMPA provides a mixed population of compact and bulgy shapes of GluA2 not impacted by addition of GYKI53655. Taken together, this suggests that the two different mechanisms of antagonism that lead to channel closure are independent and that the distribution between bulgy and compact receptors primarily depends on the ligand bound in the glutamate binding site.
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| 4. |
- Krintel, Christian, et al.
(författare)
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Structural analysis and thermodynamics of the ionotropic glutamate receptor GluA2 modulator BPAM-97
- 2011
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Ingår i: ; , s. 58-58
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ionotropic glutamate receptors are tetrameric ligand gated ion channels that mediate in ux and ef ux of metal ions in response to glutamate. Positive allosteric modulators of the ionotropic glutamate receptor 2 (GluA2) are promising lead compounds for drugs against cognitive disorders. These compounds bind within the dimeric interface formed by the receptor ligand binding domains (LBDs) attenuating deactivation and desensitisation. In this study we determined the structure of the complex formed between a dimeric GluA2 LBD-L483Y-N754S mutant and the potent novel modulator BPAM-97 by X-ray crystallography. We provide a molecular explanation for the 200 fold increased potency of BPAM-97 compared to its parent compound IDRA-21. We also utilized isothermal titration calorimetry to measure the binding af nity and thermodynamics of the LBD-L483Y-N754S:BPAM-97 complex formation as well as that for the non-dimeric LBD-N754S:BPAM-97.
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| 5. |
- Kristensen, Ole, et al.
(författare)
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Crystallization of a stringent response factor from Aquifex aeolicus.
- 2002
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Ingår i: Acta Crystallographica. Section D: Biological Crystallography. - 1399-0047. ; 58:Pt 7, s. 1198-1200
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Tidskriftsartikel (refereegranskat)abstract
- The crystallization of a key enzyme from Aquifex aeolicus with suggested bifunctional activity, acting as an exopolyphosphatase and a guanosine pentaphosphate phosphohydrolase, is reported. Native data were collected to below 2 A resolution from an orthorhombic crystal with unit-cell parameters a = 50.8, b = 70.3, c = 90.9 A. Methionine residues were introduced by mutation and deliberate oxidation of the protein allowed us to produce additional crystal forms with reproducible diffraction ability and increased phasing potential. This is the first report on the crystallization of a member of the Ppx/GppA phosphatase family.
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| 6. |
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