GTP cyclohydrolase binding / pteridine-containing compound biosynthetic process / dihydrobiopterin metabolic process / negative regulation of biosynthetic process / intracellular protein-containing complex / regulation of lung blood pressure / GTP cyclohydrolase I / GTP cyclohydrolase I activity / neuromuscular process controlling posture / regulation of removal of superoxide radicals ...GTP cyclohydrolase binding / pteridine-containing compound biosynthetic process / dihydrobiopterin metabolic process / negative regulation of biosynthetic process / intracellular protein-containing complex / regulation of lung blood pressure / GTP cyclohydrolase I / GTP cyclohydrolase I activity / neuromuscular process controlling posture / regulation of removal of superoxide radicals / GTP-dependent protein binding / tetrahydrobiopterin biosynthetic process / neuron projection terminus / regulation of nitric oxide biosynthetic process / mitogen-activated protein kinase binding / negative regulation of cardiac muscle cell apoptotic process / dopamine biosynthetic process / response to pain / negative regulation of cellular senescence / response to tumor necrosis factor / response to type II interferon / positive regulation of heart rate / tetrahydrofolate biosynthetic process / Tetrahydrobiopterin (BH4) synthesis, recycling, salvage and regulation / negative regulation of blood pressure / positive regulation of telomere maintenance via telomerase / nitric oxide biosynthetic process / positive regulation of nitric-oxide synthase activity / regulation of blood pressure / vasodilation / positive regulation of neuron apoptotic process / melanosome / protein-containing complex assembly / cytoplasmic vesicle / nuclear membrane / response to lipopolysaccharide / GTPase activity / dendrite / calcium ion binding / protein-containing complex binding / GTP binding / protein homodimerization activity / protein-containing complex / mitochondrion / zinc ion binding / nucleoplasm / identical protein binding / nucleus / cytosol / cytoplasm 類似検索 - 分子機能
GTP cyclohydrolase I, feedback regulatory protein / GFRP superfamily / GTP cyclohydrolase I feedback regulatory protein (GFRP) / GTP cyclohydrolase I signature 2. / GTP cyclohydrolase I / GTP cyclohydrolase I, conserved site / GTP cyclohydrolase I domain / GTP cyclohydrolase I, N-terminal domain / GTP cyclohydrolase I / GTP cyclohydrolase I signature 1. / GTP cyclohydrolase I, C-terminal/NADPH-dependent 7-cyano-7-deazaguanine reductase 類似検索 - ドメイン・相同性
ジャーナル: Proc Natl Acad Sci U S A / 年: 2020 タイトル: A hybrid approach reveals the allosteric regulation of GTP cyclohydrolase I. 著者: Rebecca Ebenhoch / Simone Prinz / Susann Kaltwasser / Deryck J Mills / Robert Meinecke / Martin Rübbelke / Dirk Reinert / Margit Bauer / Lisa Weixler / Markus Zeeb / Janet Vonck / Herbert Nar / 要旨: Guanosine triphosphate (GTP) cyclohydrolase I (GCH1) catalyzes the conversion of GTP to dihydroneopterin triphosphate (H2NTP), the initiating step in the biosynthesis of tetrahydrobiopterin (BH4). ...Guanosine triphosphate (GTP) cyclohydrolase I (GCH1) catalyzes the conversion of GTP to dihydroneopterin triphosphate (H2NTP), the initiating step in the biosynthesis of tetrahydrobiopterin (BH4). Besides other roles, BH4 functions as cofactor in neurotransmitter biosynthesis. The BH4 biosynthetic pathway and GCH1 have been identified as promising targets to treat pain disorders in patients. The function of mammalian GCH1s is regulated by a metabolic sensing mechanism involving a regulator protein, GCH1 feedback regulatory protein (GFRP). GFRP binds to GCH1 to form inhibited or activated complexes dependent on availability of cofactor ligands, BH4 and phenylalanine, respectively. We determined high-resolution structures of human GCH1-GFRP complexes by cryoelectron microscopy (cryo-EM). Cryo-EM revealed structural flexibility of specific and relevant surface lining loops, which previously was not detected by X-ray crystallography due to crystal packing effects. Further, we studied allosteric regulation of isolated GCH1 by X-ray crystallography. Using the combined structural information, we are able to obtain a comprehensive picture of the mechanism of allosteric regulation. Local rearrangements in the allosteric pocket upon BH4 binding result in drastic changes in the quaternary structure of the enzyme, leading to a more compact, tense form of the inhibited protein, and translocate to the active site, leading to an open, more flexible structure of its surroundings. Inhibition of the enzymatic activity is not a result of hindrance of substrate binding, but rather a consequence of accelerated substrate binding kinetics as shown by saturation transfer difference NMR (STD-NMR) and site-directed mutagenesis. We propose a dissociation rate controlled mechanism of allosteric, noncompetitive inhibition.
解像度: 1.979→160.06 Å / Cor.coef. Fo:Fc: 0.941 / Cor.coef. Fo:Fc free: 0.934 / SU R Cruickshank DPI: 0.253 / 交差検証法: THROUGHOUT / σ(F): 0 / SU R Blow DPI: 0.241 / SU Rfree Blow DPI: 0.178 / SU Rfree Cruickshank DPI: 0.183 詳細: HYDROGENS WERE FULLY REFINED WITH ZERO OCCUPANCY AT NUCLEAR POSITION. REFINEMENT NOTES. NUMBER OF REFINEMENT NOTES : 1 NOTE 1 : IDEAL-DIST CONTACT TERM CONTACT SETUP. ALL ATOMS HAVE CCP4 ATOM TYPE FROM LIBRARY