4wo0

Crystal structure of transthyretin in complex with apigenin

spinqualitylabelsall models 4wo0, resolution 1.34Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4wo0 is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.339Å Ligands: AGI Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease TTHY_HUMAN Defects in TTR are the cause of amyloidosis transthyretin-related (AMYL-TTR) [MIM:105210. A hereditary generalized amyloidosis due to transthyretin amyloid deposition. Protein fibrils can form in different tissues leading to amyloid polyneuropathies, amyloidotic cardiomyopathy, carpal tunnel syndrome, systemic senile amyloidosis. The disease includes leptomeningeal amyloidosis that is characterized by primary involvement of the central nervous system. Neuropathologic examination shows amyloid in the walls of leptomeningeal vessels, in pia arachnoid, and subpial deposits. Some patients also develop vitreous amyloid deposition that leads to visual impairment (oculoleptomeningeal amyloidosis). Clinical features include seizures, stroke-like episodes, dementia, psychomotor deterioration, variable amyloid deposition in the vitreous humor. Defects in TTR are a cause of hyperthyroxinemia dystransthyretinemic euthyroidal (HTDE) [MIM:145680. It is a condition characterized by elevation of total and free thyroxine in healthy, euthyroid persons without detectable binding protein abnormalities. Defects in TTR are a cause of carpal tunnel syndrome type 1 (CTS1) [MIM:115430. It is a condition characterized by entrapment of the median nerve within the carpal tunnel. Symptoms include burning pain and paresthesias involving the ventral surface of the hand and fingers which may radiate proximally. Impairment of sensation in the distribution of the median nerve and thenar muscle atrophy may occur. This condition may be associated with repetitive occupational trauma, wrist injuries, amyloid neuropathies, rheumatoid arthritis. Function TTHY_HUMAN Thyroid hormone-binding protein. Probably transports thyroxine from the bloodstream to the brain. Publication Abstract from PubMed Human transthyretin (TTR) represents a notable example of an amyloidogenic protein, and several compounds that are able to stabilize its native state have been proposed as effective drugs in the therapy of TTR amyloidosis. The two thyroxine (T4) binding sites present in the TTR tetramer display negative binding cooperativity. Here, structures of TTR in complex with three natural polyphenols (pterostilbene, quercetin and apigenin) have been determined, in which this asymmetry manifests itself as the presence of a main binding site with clear ligand occupancy and related electron density and a second minor site with a much lower ligand occupancy. The results of an analysis of the structural differences between the two binding sites are consistent with such a binding asymmetry. The different ability of TTR ligands to saturate the two T4 binding sites of the tetrameric protein can be ascribed to the different affinity of ligands for the weaker binding site. In comparison, the high-affinity ligand tafamidis, co-crystallized under the same experimental conditions, was able to fully saturate the two T4 binding sites. This asymmetry is characterized by the presence of small but significant differences in the conformation of the cavity of the two binding sites. Molecular-dynamics simulations suggest the presence of even larger differences in solution. Competition binding assays carried out in solution revealed the presence of a preferential binding site in TTR for the polyphenols pterostilbene and quercetin that was different from the preferential binding site for T4. The TTR binding asymmetry could possibly be exploited for the therapy of TTR amyloidosis by using a cocktail of two drugs, each of which exhibits preferential binding for a distinct binding site, thus favouring saturation of the tetrameric protein and consequently its stabilization. Structural evidence for asymmetric ligand binding to transthyretin.,Cianci M, Folli C, Zonta F, Florio P, Berni R, Zanotti G Acta Crystallogr D Biol Crystallogr. 2015 Aug 1;71(Pt 8):1582-92. doi:, 10.1107/S1399004715010585. Epub 2015 Jul 28. PMID:26249340 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Transthyretin 3D structures

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