2xwt

CRYSTAL STRUCTURE OF THE TSH RECEPTOR IN COMPLEX WITH A BLOCKING TYPE TSHR AUTOANTIBODY

spinqualitylabelsall models 2xwt, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xwt is a 3 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 1.9Å Ligands: BMA, MAN, NAG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease TSHR_HUMAN Note=Defects in TSHR are found in patients affected by hyperthyroidism with different etiologies. Somatic, constitutively activating TSHR mutations and/or constitutively activating G(s)alpha mutations have been identified in toxic thyroid nodules (TTNs) that are the predominant cause of hyperthyroidism in iodine deficient areas. These mutations lead to TSH independent activation of the cAMP cascade resulting in thyroid growth and hormone production. TSHR mutations are found in autonomously functioning thyroid nodules (AFTN), toxic multinodular goiter (TMNG) and hyperfunctioning thyroid adenomas (HTA). TMNG encompasses a spectrum of different clinical entities, ranging from a single hyperfunctioning nodule within an enlarged thyroid, to multiple hyperfunctioning areas scattered throughout the gland. HTA are discrete encapsulated neoplasms characterized by TSH-independent autonomous growth, hypersecretion of thyroid hormones, and TSH suppression. Defects in TSHR are also a cause of thyroid neoplasms (papillary and follicular cancers). Note=Autoantibodies against TSHR are directly responsible for the pathogenesis and hyperthyroidism of Graves disease. Antibody interaction with TSHR results in an uncontrolled receptor stimulation. Defects in TSHR are the cause of congenital hypothyroidism non-goitrous type 1 (CHNG1) [MIM:275200; also known as congenital hypothyroidism due to TSH resistance. CHNG1 is a non-autoimmune condition characterized by resistance to thyroid-stimulating hormone (TSH) leading to increased levels of plasma TSH and low levels of thyroid hormone. CHNG1 presents variable severity depending on the completeness of the defect. Most patients are euthyroid and asymptomatic, with a normal sized thyroid gland. Only a subset of patients develop hypothyroidism and present a hypoplastic thyroid gland. Defects in TSHR are the cause of familial gestational hyperthyroidism (HTFG) [MIM:603373. HTFG is a condition characterized by abnormally high levels of serum thyroid hormones occurring during early pregnancy. Defects in TSHR are the cause of hyperthyroidism non-autoimmune (HTNA) [MIM:609152. It is a condition characterized by abnormally high levels of serum thyroid hormones, thyroid hyperplasia, goiter and lack of anti-thyroid antibodies. Typical features of Graves disease such as exophthalmia, myxedema, antibodies anti-TSH receptor and lymphocytic infiltration of the thyroid gland are absent. Function TSHR_HUMAN Receptor for thyrothropin. Plays a central role in controlling thyroid cell metabolism. The activity of this receptor is mediated by G proteins which activate adenylate cyclase. Also acts as a receptor for thyrostimulin (GPA2+GPB5). Publication Abstract from PubMed A complex of the TSH receptor extracellular domain (amino acids 22-260; TSHR260) bound to a blocking-type human monoclonal autoantibody (K1-70) was purified, crystallised and the structure solved at 1.9 A resolution. K1-70 Fab binds to the concave surface of the TSHR leucine-rich domain (LRD) forming a large interface (2565 A(2)) with an extensive network of ionic, polar and hydrophobic interactions. Mutation of TSHR or K1-70 residues showing strong interactions in the solved structure influenced the activity of K1-70, indicating that the binding detail observed in the complex reflects interactions of K1-70 with intact, functionally active TSHR. Unbound K1-70 Fab was prepared and crystallised to 2.22 A resolution. Virtually no movement was observed in the atoms of K1-70 residues on the binding interface compared with unbound K1-70, consistent with 'lock and key' binding. The binding arrangements in the TSHR260-K1-70 Fab complex are similar to previously observed for the TSHR260-M22 Fab complex; however, K1-70 clasps the concave surface of the TSHR LRD in approximately the opposite orientation (rotated 155 degrees ) to M22. The blocking autoantibody K1-70 binds more N-terminally on the TSHR concave surface than either the stimulating autoantibody M22 or the hormone TSH, and this may reflect its different functional activity. The structure of TSHR260 in the TSHR260-K1-70 and TSHR260-M22 complexes show a root mean square deviation on all C(alpha) atoms of only 0.51 A. These high-resolution crystal structures provide a foundation for developing new strategies to understand and control TSHR activation and the autoimmune response to the TSHR. Crystal structure of the TSH receptor (TSHR) bound to a blocking-type TSHR autoantibody.,Sanders P, Young S, Sanders J, Kabelis K, Baker S, Sullivan A, Evans M, Clark J, Wilmot J, Hu X, Roberts E, Powell M, Nunez Miguel R, Furmaniak J, Rees Smith B J Mol Endocrinol. 2011 Feb 15;46(2):81-99. Print 2011. PMID:21247981 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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