1nax

Thyroid receptor beta1 in complex with a beta-selective ligandThyroid receptor beta1 in complex with a beta-selective ligand

Structural highlights 1nax is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: Related: 1nav Gene: THRB OR NR1A2 OR ERBA2 OR THR1 (Homo sapiens) Resources: FirstGlance, OCA, RCSB, PDBsum Disease [THB_HUMAN] Defects in THRB are the cause of generalized thyroid hormone resistance (GTHR) [MIM:188570]. GTHR is a disease characterized by goiter, abnormal mental functions, increased susceptibility to infections, abnormal growth and bone maturation, tachycardia and deafness. Affected individuals may also have attention deficit-hyperactivity disorders (ADHD) and language difficulties. GTHR patients also have high levels of circulating thyroid hormones (T3-T4), with normal or slightly elevated thyroid stimulating hormone (TSH). Defects in THRB are the cause of generalized thyroid hormone resistance autosomal recessive (GTHRAR) [MIM:274300]. An autosomal recessive disorder characterized by goiter, clinical euthyroidism, end-organ unresponsiveness to thyroid hormone, abnormal growth and bone maturation, and deafness. Patients also have high levels of circulating thyroid hormones, with elevated thyroid stimulating hormone. Defects in THRB are the cause of selective pituitary thyroid hormone resistance (PRTH) [MIM:145650]; also known as familial hyperthyroidism due to inappropriate thyrotropin secretion. PRTH is a variant form of thyroid hormone resistance and is characterized by clinical hyperthyroidism, with elevated free thyroid hormones, but inappropriately normal serum TSH. Unlike GRTH, where the syndrome usually segregates with a dominant allele, the mode of inheritance in PRTH has not been established. Function [THB_HUMAN] High affinity receptor for triiodothyronine. 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 PubMed Endogenous thyroid receptor hormones 3,5,3',5'-tetraiodo-l-thyronine (T(4), 1) and 3,5,3'-triiodo-l-thyronine (T(3), 2) exert a significant effects on growth, development, and homeostasis in mammals. They regulate important genes in intestinal, skeletal, and cardiac muscles, the liver, and the central nervous system, influence overall metabolic rate, cholesterol and triglyceride levels, and heart rate, and affect mood and overall sense of well being. The literature suggests many or most effects of thyroid hormones on the heart, in particular on the heart rate and rhythm, are mediated through the TRalpha(1) isoform, while most actions of the hormones on the liver and other tissues are mediated more through the TRbeta(1) isoform of the receptor. Some effects of thyroid hormones may be therapeutically useful in nonthyroid disorders if adverse effects can be minimized or eliminated. These potentially useful features include weight reduction for the treatment of obesity, cholesterol lowering for treating hyperlipidemia, amelioration of depression, and stimulation of bone formation in osteoporosis. Prior attempts to utilize thyroid hormones pharmacologically to treat these disorders have been limited by manifestations of hyperthyroidism and, in particular, cardiovascular toxicity. Consequently, development of thyroid hormone receptor agonists that are selective for the beta-isoform could lead to safe therapies for these common disorders while avoiding cardiotoxicity. We describe here the synthesis and evaluation of a series of novel TR ligands, which are selective for TRbeta(1) over TRalpha(1). These ligands could potentially be useful for treatment of various disorders as outlined above. From a series of homologous R(1)-substituted carboxylic acid derivatives, increasing chain length was found to have a profound effect on affinity and selectivity in a radioreceptor binding assay for the human thyroid hormone receptors alpha(1) and beta(1) (TRalpha(1) and TRbeta(2)) as well as a reporter cell assay employing CHOK1-cells (Chinese hamster ovary cells) stably transfected with hTRalpha(1) or hTRbeta(1) and an alkaline phosphatase reporter-gene downstream thyroid response element (TRAFalpha(1) and TRAFbeta(1)). Affinity increases in the order formic, acetic, and propionic acid, while beta-selectivity is highest when the R(1) position is substituted with acetic acid. Within this series 3,5-dibromo-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (11a) and 3,5-dichloro-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (15) were found to reveal the most promising in vitro data based on isoform selectivity and were selected for further in vivo studies. The effect of 2, 11a, and 15 in a cholesterol-fed rat model was monitored including potencies for heart rate (ED(15)), cholesterol (ED(50)), and TSH (ED(50)). Potency for tachycardia was significantly reduced for the TRbeta selective compounds 11a and 15 compared with 2, while both 11a and 15 retained the cholesterol-lowering potency of 2. This left an approximately 10-fold therapeutic window between heart rate and cholesterol, which is consistent with the action of ligands that are approximately 10-fold more selective for TRbeta(1). We also report the X-ray crystallographic structures of the ligand binding domains of TRalpha and TRbeta in complex with 15. These structures reveal that the single amino acid difference in the ligand binding pocket (Ser277 in TRalpha or Asn331 in TRbeta) results in a slightly different hydrogen bonding pattern that may explain the increased beta-selectivity of 15. Thyroid receptor ligands. 1. Agonist ligands selective for the thyroid receptor beta1.,Ye L, Li YL, Mellstrom K, Mellin C, Bladh LG, Koehler K, Garg N, Garcia Collazo AM, Litten C, Husman B, Persson K, Ljunggren J, Grover G, Sleph PG, George R, Malm J J Med Chem. 2003 Apr 24;46(9):1580-8. PMID:12699376 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

spinqualitylabelsall models 1nax, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image