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Open data
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Basic information
Entry | Database: PDB / ID: 6z85 | ||||||
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Title | inhibitory human GTP cyclohydrolase I - GFRP complex | ||||||
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Function / homology | ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Similarity search - Function | ||||||
Biological species | ![]() ![]() | ||||||
Method | ![]() ![]() ![]() | ||||||
![]() | Ebenhoch, R. / Nar, H. / Vonck, J. | ||||||
![]() | ![]() Title: A hybrid approach reveals the allosteric regulation of GTP cyclohydrolase I. Authors: 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 / ![]() Abstract: 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. | ||||||
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Structure visualization
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Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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PDBx/mmCIF format | ![]() | 562.8 KB | Display | ![]() |
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PDB format | ![]() | 414.2 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
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-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 11114MC ![]() 6z80C ![]() 6z86C ![]() 6z87C ![]() 6z88C ![]() 6z89C ![]() 7accC ![]() 7al9C ![]() 7alaC ![]() 7albC ![]() 7alcC M: map data used to model this data C: citing same article ( |
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Similar structure data |
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Links
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Assembly
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Components
#1: Protein | ![]() Mass: 25324.920 Da / Num. of mol.: 10 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() ![]() ![]() #2: Protein | Mass: 9992.483 Da / Num. of mol.: 10 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() ![]() #3: Chemical | ChemComp-ZN / #4: Chemical | ChemComp-HBI / ![]() Has ligand of interest | Y | |
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-Experimental details
-Experiment
Experiment | Method: ![]() |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: ![]() |
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Sample preparation
Component | Name: inhibitory GCH1-GFRP complex (BH4 bound) / Type: COMPLEX / Entity ID: #1-#2 / Source: MULTIPLE SOURCES | |||||||||||||||
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Molecular weight | Value: 0.353 MDa / Experimental value: NO | |||||||||||||||
Source (natural) | Organism: ![]() ![]() | |||||||||||||||
Source (recombinant) | Organism: ![]() ![]() ![]() | |||||||||||||||
Buffer solution | pH: 5.75 | |||||||||||||||
Buffer component |
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Specimen | Conc.: 0.25 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied![]() ![]() | |||||||||||||||
Specimen support | Grid material: COPPER / Grid mesh size: 400 divisions/in. / Grid type: C-flat-1.2/1.3 | |||||||||||||||
Vitrification![]() | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 90 % / Chamber temperature: 277.15 K |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source![]() ![]() |
Electron lens | Mode: BRIGHT FIELD![]() ![]() |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Average exposure time: 8 sec. / Electron dose: 55 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Num. of grids imaged: 1 / Num. of real images: 2688 |
EM imaging optics | Energyfilter name![]() |
Image scans | Movie frames/image: 40 |
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Processing
Software | Name: PHENIX / Version: (1.13_2998:phenix.real_space_refine) / Classification: refinement | ||||||||||||||||||||||||||||||||||||||||
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EM software |
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CTF correction![]() | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 1871460 | ||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry![]() ![]() | ||||||||||||||||||||||||||||||||||||||||
3D reconstruction![]() | Resolution: 2.9 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 560802 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: RIGID BODY FIT | ||||||||||||||||||||||||||||||||||||||||
Atomic model building |
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Refinement | Cross valid method: THROUGHOUT | ||||||||||||||||||||||||||||||||||||||||
Displacement parameters | Biso max: 0 Å2 / Biso mean: 0 Å2 / Biso min: 0 Å2 | ||||||||||||||||||||||||||||||||||||||||
Refine LS restraints |
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