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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-3906 | |||||||||
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Title | Cryo-EM density map of the human PLC editing module | |||||||||
![]() | CryoEM map of a protein complex | |||||||||
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![]() | adaptive immunity / antigen processing / chaperone / MHC class I / IMMUNE SYSTEM | |||||||||
Function / homology | ![]() MHC class Ib protein complex assembly / peptide antigen stabilization / Tapasin-ERp57 complex / Calnexin/calreticulin cycle / MHC class I protein complex binding / TAP1 binding / TAP2 binding / cytolytic granule / positive regulation of dendritic cell chemotaxis / protein disulfide-isomerase ...MHC class Ib protein complex assembly / peptide antigen stabilization / Tapasin-ERp57 complex / Calnexin/calreticulin cycle / MHC class I protein complex binding / TAP1 binding / TAP2 binding / cytolytic granule / positive regulation of dendritic cell chemotaxis / protein disulfide-isomerase / cortical granule / Assembly of Viral Components at the Budding Site / negative regulation of trophoblast cell migration / ATF6 (ATF6-alpha) activates chaperone genes / negative regulation of retinoic acid receptor signaling pathway / cellular response to electrical stimulus / endoplasmic reticulum quality control compartment / nuclear receptor-mediated glucocorticoid signaling pathway / regulation of meiotic nuclear division / complement component C1q complex binding / sequestering of calcium ion / response to glycoside / sarcoplasmic reticulum lumen / disulfide oxidoreductase activity / protein folding in endoplasmic reticulum / nuclear export signal receptor activity / negative regulation of intracellular steroid hormone receptor signaling pathway / regulation of protein complex stability / hormone binding / cardiac muscle cell differentiation / molecular sequestering activity / phospholipase C activity / retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum / positive regulation of extrinsic apoptotic signaling pathway / cellular response to interleukin-7 / protein maturation by protein folding / Scavenging by Class F Receptors / Scavenging by Class A Receptors / cortical actin cytoskeleton organization / T cell mediated cytotoxicity directed against tumor cell target / positive regulation of memory T cell activation / TAP complex binding / nuclear androgen receptor binding / positive regulation of CD8-positive, alpha-beta T cell activation / CD8-positive, alpha-beta T cell activation / Golgi medial cisterna / positive regulation of CD8-positive, alpha-beta T cell proliferation / cellular response to lithium ion / CD8 receptor binding / response to testosterone / protein disulfide isomerase activity / MHC class I protein binding / antigen processing and presentation of exogenous peptide antigen via MHC class I / endoplasmic reticulum exit site / antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-dependent / TAP binding / protein localization to nucleus / protection from natural killer cell mediated cytotoxicity / negative regulation of neuron differentiation / protein-disulfide reductase activity / smooth endoplasmic reticulum / beta-2-microglobulin binding / T cell receptor binding / positive regulation of cell cycle / detection of bacterium / ERAD pathway / extrinsic apoptotic signaling pathway / positive regulation of substrate adhesion-dependent cell spreading / protein folding chaperone / positive regulation of phagocytosis / endocytic vesicle lumen / protein export from nucleus / phagocytic vesicle / positive regulation of endothelial cell migration / endoplasmic reticulum-Golgi intermediate compartment membrane / response to endoplasmic reticulum stress / acrosomal vesicle / positive regulation of ferrous iron binding / positive regulation of transferrin receptor binding / positive regulation of receptor binding / early endosome lumen / Nef mediated downregulation of MHC class I complex cell surface expression / DAP12 interactions / negative regulation of receptor binding / antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-independent / antigen processing and presentation of endogenous peptide antigen via MHC class Ib / lumenal side of endoplasmic reticulum membrane / cellular response to iron ion / Endosomal/Vacuolar pathway / Antigen Presentation: Folding, assembly and peptide loading of class I MHC / peptide binding / cellular response to iron(III) ion / antigen processing and presentation of exogenous protein antigen via MHC class Ib, TAP-dependent / negative regulation of forebrain neuron differentiation / regulation of erythrocyte differentiation / ER to Golgi transport vesicle membrane / peptide antigen assembly with MHC class I protein complex / regulation of iron ion transport / response to molecule of bacterial origin / MHC class I peptide loading complex Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 5.8 Å | |||||||||
![]() | Januliene D / Blees A / Trowitzsch S / Tampe R / Moeller A | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structure of the human MHC-I peptide-loading complex. Authors: Andreas Blees / Dovile Januliene / Tommy Hofmann / Nicole Koller / Carla Schmidt / Simon Trowitzsch / Arne Moeller / Robert Tampé / ![]() Abstract: The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates ...The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates peptide translocation into the endoplasmic reticulum with loading and editing of major histocompatibility complex class I (MHC-I) molecules. After final proofreading in the PLC, stable peptide-MHC-I complexes are released to the cell surface to evoke a T-cell response against infected or malignant cells. Sampling of different MHC-I allomorphs requires the precise coordination of seven different subunits in a single macromolecular assembly, including the transporter associated with antigen processing (TAP1 and TAP2, jointly referred to as TAP), the oxidoreductase ERp57, the MHC-I heterodimer, and the chaperones tapasin and calreticulin. The molecular organization of and mechanistic events that take place in the PLC are unknown owing to the heterogeneous composition and intrinsically dynamic nature of the complex. Here, we isolate human PLC from Burkitt's lymphoma cells using an engineered viral inhibitor as bait and determine the structure of native PLC by electron cryo-microscopy. Two endoplasmic reticulum-resident editing modules composed of tapasin, calreticulin, ERp57, and MHC-I are centred around TAP in a pseudo-symmetric orientation. A multivalent chaperone network within and across the editing modules establishes the proofreading function at two lateral binding platforms for MHC-I molecules. The lectin-like domain of calreticulin senses the MHC-I glycan, whereas the P domain reaches over the MHC-I peptide-binding pocket towards ERp57. This arrangement allows tapasin to facilitate peptide editing by clamping MHC-I. The translocation pathway of TAP opens out into a large endoplasmic reticulum lumenal cavity, confined by the membrane entry points of tapasin and MHC-I. Two lateral windows channel the antigenic peptides to MHC-I. Structures of PLC captured at distinct assembly states provide mechanistic insight into the recruitment and release of MHC-I. Our work defines the molecular symbiosis of an ABC transporter and an endoplasmic reticulum chaperone network in MHC-I assembly and provides insight into the onset of the adaptive immune response. | |||||||||
History |
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Structure visualization
Movie |
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 25.5 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 16 KB 16 KB | Display Display | ![]() |
Images | ![]() | 44.5 KB | ||
Filedesc metadata | ![]() | 6.6 KB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Validation report
Summary document | ![]() | 225.2 KB | Display | ![]() |
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Full document | ![]() | 224.3 KB | Display | |
Data in XML | ![]() | 5.7 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 6enyMC ![]() 3904C ![]() 3905C C: citing same article ( M: atomic model generated by this map |
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Similar structure data |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Annotation | CryoEM map of a protein complex | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.077 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
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Sample components
-Entire : Protein Complex
Entire | Name: Protein Complex |
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Components |
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-Supramolecule #1: Protein Complex
Supramolecule | Name: Protein Complex / type: complex / ID: 1 / Parent: 0 / Macromolecule list: all |
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Source (natural) | Organism: ![]() |
-Macromolecule #1: Beta-2-microglobulin
Macromolecule | Name: Beta-2-microglobulin / type: protein_or_peptide / ID: 1 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 11.74816 KDa |
Sequence | String: IQRTPKIQVY SRHPAENGKS NFLNCYVSGF HPSDIEVDLL KNGERIEKVE HSDLSFSKDW SFYLLYYTEF TPTEKDEYAC RVNHVTLSQ PKIVKWDRDM UniProtKB: Beta-2-microglobulin |
-Macromolecule #2: Tapasin
Macromolecule | Name: Tapasin / type: protein_or_peptide / ID: 2 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 45.761184 KDa |
Sequence | String: GPAVIECWFV EDASGKGLAK RPGALLLRQG PGEPPPRPDL DPELYLSVHD PAGALQAAFR RYPRGAPAPH CEMSRFVPLP ASAKWASGL TPAQNCPRAL DGAWLMVSIS SPVLSLSSLL RPQPEPQQEP VLITMATVVL TVLTHTPAPR VRLGQDALLD L SFAYMPPT ...String: GPAVIECWFV EDASGKGLAK RPGALLLRQG PGEPPPRPDL DPELYLSVHD PAGALQAAFR RYPRGAPAPH CEMSRFVPLP ASAKWASGL TPAQNCPRAL DGAWLMVSIS SPVLSLSSLL RPQPEPQQEP VLITMATVVL TVLTHTPAPR VRLGQDALLD L SFAYMPPT SEAASSLAPG PPPFGLEWRR QHLGKGHLLL AATPGLNGQM PAAQEGAVAF AAWDDDEPWG PWTGNGTFWL PR VQPFQEG TYLATIHLPY LQGQVTLELA VYKPPKVSLM PATLARAAPG EAPPELLCLV SHFYPSGGLE VEWELRGGPG GRS QKAEGQ RWLSALRHHS DGSVSLSGHL QPPPVTTEQH GARYACRIHH PSLPASGRSA EVTLEVAGLS GPSLEDSVGL FLSA FLLLG LFKALGWAAV YLSTCKDSKK KAE UniProtKB: Tapasin |
-Macromolecule #3: Protein disulfide-isomerase A3
Macromolecule | Name: Protein disulfide-isomerase A3 / type: protein_or_peptide / ID: 3 / Number of copies: 1 / Enantiomer: LEVO / EC number: protein disulfide-isomerase |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 54.341102 KDa |
Sequence | String: SDVLELTDDN FESRISDTGS AGLMLVEFFA PWCGHCKRLA PEYEAAATRL KGIVPLAKVD CTANTNTCNK YGVSGYPTLK IFRDGEEAG AYDGPRTADG IVSHLKKQAG PASVPLRTEE EFKKFISDKD ASIVGFFDDS FSEAHSEFLK AASNLRDNYR F AHTNVESL ...String: SDVLELTDDN FESRISDTGS AGLMLVEFFA PWCGHCKRLA PEYEAAATRL KGIVPLAKVD CTANTNTCNK YGVSGYPTLK IFRDGEEAG AYDGPRTADG IVSHLKKQAG PASVPLRTEE EFKKFISDKD ASIVGFFDDS FSEAHSEFLK AASNLRDNYR F AHTNVESL VNEYDDNGEG IILFRPSHLT NKFEDKTVAY TEQKMTSGKI KKFIQENIFG ICPHMTEDNK DLIQGKDLLI AY YDVDYEK NAKGSNYWRN RVMMVAKKFL DAGHKLNFAV ASRKTFSHEL SDFGLESTAG EIPVVAIRTA KGEKFVMQEE FSR DGKALE RFLQDYFDGN LKRYLKSEPI PESNDGPVKV VVAENFDEIV NNENKDVLIE FYAPWCGHCK NLEPKYKELG EKLS KDPNI VIAKMDATAN DVPSPYEVRG FPTIYFSPAN KKLNPKKYEG GRELSDFISY LQREATNPPV IQEEKPKKKK KAQED L UniProtKB: Protein disulfide-isomerase A3 |
-Macromolecule #4: HLA class I histocompatibility antigen, A-3 alpha chain
Macromolecule | Name: HLA class I histocompatibility antigen, A-3 alpha chain type: protein_or_peptide / ID: 4 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 38.363535 KDa |
Sequence | String: GSHSMRYFFT SVSRPGRGEP RFIAVGYVDD TQFVRFDSDA ASQRMEPRAP WIEQEGPEYW DQETRNVKAQ SQTDRVDLGT LRGYYNQSE AGSHTIQIMY GCDVGSDGRF LRGYRQDAYD GKDYIALNED LRSWTAADMA AQITKRKWEA AHEAEQLRAY L DGTCVEWL ...String: GSHSMRYFFT SVSRPGRGEP RFIAVGYVDD TQFVRFDSDA ASQRMEPRAP WIEQEGPEYW DQETRNVKAQ SQTDRVDLGT LRGYYNQSE AGSHTIQIMY GCDVGSDGRF LRGYRQDAYD GKDYIALNED LRSWTAADMA AQITKRKWEA AHEAEQLRAY L DGTCVEWL RRYLENGKET LQRTDPPKTH MTHHPISDHE ATLRCWALGF YPAEITLTWQ RDGEDQTQDT ELVETRPAGD GT FQKWAAV VVPSGEEQRY TCHVQHEGLP KPLTLRWELS SQPTIPIVGI IAGLVLLGAV ITGAVVAAVM WRRKSSDRKG GSY TQAASS DSAQGSDVSL TACKV UniProtKB: HLA class I histocompatibility antigen, A alpha chain |
-Macromolecule #5: Calreticulin
Macromolecule | Name: Calreticulin / type: protein_or_peptide / ID: 5 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 46.507145 KDa |
Sequence | String: EPAVYFKEQF LDGDGWTSRW IESKHKSDFG KFVLSSGKFY GDEEKDKGLQ TSQDARFYAL SASFEPFSNK GQTLVVQFTV KHEQNIDCG GGYVKLFPNS LDQTDMHGDS EYNIMFGPDI CGPGTKKVHV IFNYKGKNVL INKDIRSKDD EFTHLYTLIV R PDNTYEVK ...String: EPAVYFKEQF LDGDGWTSRW IESKHKSDFG KFVLSSGKFY GDEEKDKGLQ TSQDARFYAL SASFEPFSNK GQTLVVQFTV KHEQNIDCG GGYVKLFPNS LDQTDMHGDS EYNIMFGPDI CGPGTKKVHV IFNYKGKNVL INKDIRSKDD EFTHLYTLIV R PDNTYEVK IDNSQVESGS LEDDWDFLPP KKIKDPDASK PEDWDERAKI DDPTDSKPED WDKPEHIPDP DAKKPEDWDE EM DGEWEPP VIQNPEYKGE WKPRQIDNPD YKGTWIHPEI DNPEYSPDPS IYAYDNFGVL GLDLWQVKSG TIFDNFLITN DEA YAEEFG NETWGVTKAA EKQMKDKQDE EQRLKEEEED KKRKEEEEAE DKEDDEDKDE DEEDEEDKEE DEEEDVPGQA KDEL UniProtKB: Calreticulin |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 2 mg/mL |
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Buffer | pH: 7.5 |
Grid | Model: C-flat-2/2 / Pretreatment - Type: GLOW DISCHARGE |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K2 QUANTUM (4k x 4k) / Detector mode: COUNTING / Average electron dose: 55.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: OTHER Details: Selected particles from the best 2D class averages were subjected to 3D-classification in Relion, using a low-pass filtered global average as a starting model. The best map was then used as ...Details: Selected particles from the best 2D class averages were subjected to 3D-classification in Relion, using a low-pass filtered global average as a starting model. The best map was then used as an initial model for subsequent 3D classification. |
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Final reconstruction | Applied symmetry - Point group: C1 (asymmetric) / Resolution.type: BY AUTHOR / Resolution: 5.8 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: FREALIGN (ver. X) / Number images used: 141078 |
Initial angle assignment | Type: ANGULAR RECONSTITUTION / Software - Name: RELION (ver. 2.1) |
Final angle assignment | Type: ANGULAR RECONSTITUTION |