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Open data
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Basic information
| Entry | ![]() | |||||||||
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| Title | Porcine Retinol-Binding Protein 3 (RBP3) | |||||||||
Map data | The map with the RBP3 rigid core refined. | |||||||||
Sample |
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Keywords | Retinoids / Interphotoreceptor matrix (IPM) / Visual cycle / Shuttle / TRANSPORT PROTEIN | |||||||||
| Function / homology | Function and homology informationinterphotoreceptor matrix / retinal binding / serine-type peptidase activity / proteolysis / extracellular region Similarity search - Function | |||||||||
| Biological species | ![]() | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.67 Å | |||||||||
Authors | Kaushik V / Gessa L / Kumar N / Pinkas M / Czarnocki-Cieciura M / Palczewski K / Novacek J / Fernandes H | |||||||||
| Funding support | Poland, European Union, 2 items
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Citation | Journal: Open Biol / Year: 2025Title: CryoEM structure and small-angle X-ray scattering analyses of porcine retinol-binding protein 3. Authors: Vineeta Kaushik / Luca Gessa / Nelam Kumar / Matyáš Pinkas / Mariusz Czarnocki-Cieciura / Krzysztof Palczewski / Jiří Nováček / Humberto Fernandes / ![]() Abstract: The vertebrate visual cycle hinges on enzymatically converting all--retinol (at-ROL) into 11--retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive ...The vertebrate visual cycle hinges on enzymatically converting all--retinol (at-ROL) into 11--retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive pigments. When struck by a photon, these pigments activate the phototransduction pathway and initiate the process of vision. The enzymatic isomerization of at-ROL, crucial for restoring the visual pigments and preparing them to receive new light stimuli, relies on various enzymes found in both the photoreceptors and retinal pigment epithelium cells. To function effectively, retinoids must shuttle between these two cell types. Retinol-binding protein 3 (RBP3), located in the interphotoreceptor matrix, probably plays a pivotal role in this transport mechanism. Comprised of four retinoid-binding modules, RBP3 also binds fatty acids, potentially aiding retinal function by facilitating the loading and unloading of different retinoids at specific cell types thereby directing the cycle. In this study, we present a 3.67 Å cryoEM structure of porcine RBP3, along with molecular docking analysis and corroborative in-solution small-angle X-ray scattering data for titration of RBP3 with relevant ligands, that also give insights on RBP3 conformational adaptability. | |||||||||
| History |
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Structure visualization
| Supplemental images |
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Downloads & links
-EMDB archive
| Map data | emd_50552.map.gz | 226.5 MB | EMDB map data format | |
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| Header (meta data) | emd-50552-v30.xml emd-50552.xml | 23.2 KB 23.2 KB | Display Display | EMDB header |
| FSC (resolution estimation) | emd_50552_fsc.xml | 14.2 KB | Display | FSC data file |
| Images | emd_50552.png | 65.9 KB | ||
| Masks | emd_50552_msk_1.map | 244.1 MB | Mask map | |
| Filedesc metadata | emd-50552.cif.gz | 6.4 KB | ||
| Others | emd_50552_additional_1.map.gz emd_50552_additional_2.map.gz emd_50552_half_map_1.map.gz emd_50552_half_map_2.map.gz | 12.8 MB 228.3 MB 226.8 MB 226.8 MB | ||
| Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-50552 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-50552 | HTTPS FTP |
-Validation report
| Summary document | emd_50552_validation.pdf.gz | 945.1 KB | Display | EMDB validaton report |
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| Full document | emd_50552_full_validation.pdf.gz | 944.7 KB | Display | |
| Data in XML | emd_50552_validation.xml.gz | 20.7 KB | Display | |
| Data in CIF | emd_50552_validation.cif.gz | 26.4 KB | Display | |
| Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-50552 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-50552 | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 9frxMC M: atomic model generated by this map C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
| EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Map
| File | Download / File: emd_50552.map.gz / Format: CCP4 / Size: 244.1 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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| Annotation | The map with the RBP3 rigid core refined. | ||||||||||||||||||||||||||||||||||||
| Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.834 Å | ||||||||||||||||||||||||||||||||||||
| Density |
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML:
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-Supplemental data
-Mask #1
| File | emd_50552_msk_1.map | ||||||||||||
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| Density Histograms |
-Additional map: The joint map of the RBP3 rigid map's...
| File | emd_50552_additional_1.map | ||||||||||||
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| Annotation | The joint map of the RBP3 rigid map's core and the RBP3 flexible maps' arms. | ||||||||||||
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| Density Histograms |
-Additional map: The map of the refinement focused on the flexible arms of RBP3.
| File | emd_50552_additional_2.map | ||||||||||||
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| Annotation | The map of the refinement focused on the flexible arms of RBP3. | ||||||||||||
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| Density Histograms |
-Half map: The second half map of the refinement of the RBP3 rigid core.
| File | emd_50552_half_map_1.map | ||||||||||||
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| Annotation | The second half map of the refinement of the RBP3 rigid core. | ||||||||||||
| Projections & Slices |
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| Density Histograms |
-Half map: The first half map of the refinement of the RBP3 rigid core.
| File | emd_50552_half_map_2.map | ||||||||||||
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| Annotation | The first half map of the refinement of the RBP3 rigid core. | ||||||||||||
| Projections & Slices |
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| Density Histograms |
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Sample components
-Entire : Retinol binding protein 3
| Entire | Name: Retinol binding protein 3 |
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| Components |
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-Supramolecule #1: Retinol binding protein 3
| Supramolecule | Name: Retinol binding protein 3 / type: organelle_or_cellular_component / ID: 1 / Parent: 0 / Macromolecule list: all |
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| Source (natural) | Organism: ![]() |
| Molecular weight | Theoretical: 135 kDa/nm |
-Macromolecule #1: Retinol binding protein 3
| Macromolecule | Name: Retinol binding protein 3 / type: protein_or_peptide / ID: 1 / Enantiomer: LEVO |
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| Source (natural) | Organism: ![]() |
| Sequence | String: MPRKWALLLP MLLCSLTGPT HMFQSSLVLD TAKILLDNYC FPENLMGMQE AIEQATKSPE ILAITDPQT LAHVLTAGVQ NSLNDPRLII SYEPSTLEVT PKAPALRNLT LEELIEGLHN S LRHEVLEG NVGYLRVDDI PGQEVMNKLG SFLVVNVWEK LMGTSALVLD ...String: MPRKWALLLP MLLCSLTGPT HMFQSSLVLD TAKILLDNYC FPENLMGMQE AIEQATKSPE ILAITDPQT LAHVLTAGVQ NSLNDPRLII SYEPSTLEVT PKAPALRNLT LEELIEGLHN S LRHEVLEG NVGYLRVDDI PGQEVMNKLG SFLVVNVWEK LMGTSALVLD LRHCTRGHVS GI PYVISYL HPGNTVLHVD TVYDRPSNTT TEIWTLPEVL GDRYSADKDV VVLTSSHTGG VAE DIAYIL KQMRRAIVVG ERTVGGALDL QKLRIGQSDF FLTVPVSRSL GPLGEGSQTW EGSG VLPCV GTPAEQALEK ALAILKLRRA LPGVIQRLQE VLQEYYTLVD RVPALLHHLA SMDLS SVVS EEDLVTKLNA GLQAVSEDPR LLVQVVKSKE PSSEPKDEAE EPPEVIPEVP EDEAAR RAL VDAVFQVSVL PGNVGYLRFD SFADASVLGV LAPYIVHQVW EPLQDTEHLI MDLRQNP GG PSTAVPLLLS YFQGPDPGPV RLFTTYDRRT NVTQEHYSHT ELLGQRYSTQ GGVYLLIS H RTATAAEELA FLMQSLGWAT LVGEITAGSL LHTHTVPLLE TTEGGLSLTV PVLTFIDNH GECWLGGGVV PDAIVLAEEA LDRAQEVLEF HRSLGELVEG TGHLLEAHYA RPEVVGQTGA LLRAKLAQG AYRTAVDLES LASQLTADLQ EMSGDHRLLV FHSPGEMVAE EVPPPPPVVP S PEELSYLI EALFKTEVLP GRLGYLRFDA MAELETVKAI GPQLVQLVWQ KLIDTAALVV DL RYNPGSY STAVPLLCSY FFEAEPRQHL YSVFDRATSR VMEVWTVPQV AGQRYGPQKD LYI LVSHTS GSAAEAFAHT MQDLQRATII GEPTAGGALS VGIYQVGSSP LYASMPTQMA LSAS TGEAW DLAGVEPDIT VPMSVALSTA RDIVALRAKV PTVLQTAGKL VADNYASPEM GAKIA VKLS RLQSRYARVT SEASLAEMLE ADLQLLSGDP HLKTAHIPED AKDRIPGIVP MQIPSP EVF EDLIKFSFHT NVLEGNIGYL RFDMFGDREL LTQVSELLVE HVWKKIIHTD ALIIDMR FN IGGPTSSISA LCSYFFDEGP PILLDKIYNR PNDSVSELWT HTHLTGGSYG SKKSIIIL T SSLTAGAAEE FTYIMKRLGR ALVIGEVTSG GSQPPQTYHV DDTNLYITIP TARSVGAAD GSSWEGVGVV PDVAVPAEGA LARAQEMLQH TLLRARRSLQ DHKPTLFKQE SPDRRQAFTP APFLLAKSK UniProtKB: Retinol-binding protein 3 |
-Experimental details
-Structure determination
| Method | cryo EM |
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Processing | single particle reconstruction |
| Aggregation state | particle |
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Sample preparation
| Concentration | 0.9 mg/mL | ||||||||||||
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| Buffer | pH: 8 Component:
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| Grid | Model: Quantifoil R2/1 / Material: COPPER / Mesh: 200 / Pretreatment - Type: GLOW DISCHARGE | ||||||||||||
| Vitrification | Cryogen name: ETHANE / Chamber humidity: 95 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV |
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Electron microscopy
| Microscope | TFS KRIOS |
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| Specialist optics | Energy filter - Name: GIF Bioquantum / Energy filter - Slit width: 10 eV |
| Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Digitization - Dimensions - Width: 5760 pixel / Digitization - Dimensions - Height: 4092 pixel / Number grids imaged: 2 / Number real images: 23606 / Average exposure time: 2.0 sec. / Average electron dose: 40.0 e/Å2 |
| Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
| Electron optics | C2 aperture diameter: 30.0 µm / Calibrated defocus max: 3.0 µm / Calibrated defocus min: 1.4000000000000001 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 3.0 µm / Nominal defocus min: 1.4000000000000001 µm / Nominal magnification: 105000 |
| Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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About Yorodumi




Keywords
Authors
Poland, European Union, 2 items
Citation


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Processing
FIELD EMISSION GUN

