+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-17209 | |||||||||
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Title | Human Complement C3b in complex with Trypanosoma brucei ISG65. | |||||||||
Map data | Human Complement C3 in complex with T. brucei ISG65. Composite map from local alignments of the CUB-TED-ISG65 and remaining C3b regions. Postprocessed in DeepEMhancer. | |||||||||
Sample |
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Keywords | Complement system / parasite virulence / trypanosome surface protein / host-pathogen complex / IMMUNE SYSTEM | |||||||||
Function / homology | Function and homology information C5L2 anaphylatoxin chemotactic receptor binding / oviduct epithelium development / regulation of triglyceride biosynthetic process / positive regulation of activation of membrane attack complex / vertebrate eye-specific patterning / positive regulation of apoptotic cell clearance / complement-mediated synapse pruning / Alternative complement activation / positive regulation of lipid storage / positive regulation of phagocytosis, engulfment ...C5L2 anaphylatoxin chemotactic receptor binding / oviduct epithelium development / regulation of triglyceride biosynthetic process / positive regulation of activation of membrane attack complex / vertebrate eye-specific patterning / positive regulation of apoptotic cell clearance / complement-mediated synapse pruning / Alternative complement activation / positive regulation of lipid storage / positive regulation of phagocytosis, engulfment / positive regulation of G protein-coupled receptor signaling pathway / Activation of C3 and C5 / complement receptor mediated signaling pathway / positive regulation of type IIa hypersensitivity / positive regulation of D-glucose transmembrane transport / complement-dependent cytotoxicity / complement activation / complement activation, alternative pathway / endopeptidase inhibitor activity / neuron remodeling / B cell activation / amyloid-beta clearance / positive regulation of vascular endothelial growth factor production / Purinergic signaling in leishmaniasis infection / complement activation, classical pathway / Peptide ligand-binding receptors / Regulation of Complement cascade / fatty acid metabolic process / Post-translational protein phosphorylation / response to bacterium / positive regulation of receptor-mediated endocytosis / positive regulation of angiogenesis / Regulation of Insulin-like Growth Factor (IGF) transport and uptake by Insulin-like Growth Factor Binding Proteins (IGFBPs) / Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell / azurophil granule lumen / G alpha (i) signalling events / secretory granule lumen / blood microparticle / receptor ligand activity / inflammatory response / immune response / positive regulation of protein phosphorylation / G protein-coupled receptor signaling pathway / endoplasmic reticulum lumen / signaling receptor binding / Neutrophil degranulation / cell surface / signal transduction / protein-containing complex / extracellular space / extracellular exosome / extracellular region / membrane / plasma membrane Similarity search - Function | |||||||||
Biological species | Homo sapiens (human) / Trypanosoma brucei brucei (eukaryote) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.4 Å | |||||||||
Authors | Cook AD / Higgins MK | |||||||||
Funding support | United Kingdom, 1 items
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Citation | Journal: Elife / Year: 2024 Title: Molecular mechanism of complement inhibition by the trypanosome receptor ISG65. Authors: Alexander D Cook / Mark Carrington / Matthew K Higgins / Abstract: African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but ...African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade. | |||||||||
History |
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-Structure visualization
Supplemental images |
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-Downloads & links
-EMDB archive
Map data | emd_17209.map.gz | 118.8 MB | EMDB map data format | |
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Header (meta data) | emd-17209-v30.xml emd-17209.xml | 19.2 KB 19.2 KB | Display Display | EMDB header |
Images | emd_17209.png | 158.7 KB | ||
Filedesc metadata | emd-17209.cif.gz | 7.6 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-17209 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-17209 | HTTPS FTP |
-Validation report
Summary document | emd_17209_validation.pdf.gz | 359.9 KB | Display | EMDB validaton report |
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Full document | emd_17209_full_validation.pdf.gz | 359.5 KB | Display | |
Data in XML | emd_17209_validation.xml.gz | 6.7 KB | Display | |
Data in CIF | emd_17209_validation.cif.gz | 7.8 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-17209 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-17209 | HTTPS FTP |
-Related structure data
Related structure data | 8ovbMC C: citing same article (ref.) M: atomic model generated by this map |
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Similar structure data | Similarity search - Function & homologyF&H Search |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_17209.map.gz / Format: CCP4 / Size: 144.7 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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Annotation | Human Complement C3 in complex with T. brucei ISG65. Composite map from local alignments of the CUB-TED-ISG65 and remaining C3b regions. Postprocessed in DeepEMhancer. | ||||||||||||||||||||||||||||||||||||
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.832 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Sample components
-Entire : Complex of Human Complement C3b and T. brucei ISG65
Entire | Name: Complex of Human Complement C3b and T. brucei ISG65 |
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Components |
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-Supramolecule #1: Complex of Human Complement C3b and T. brucei ISG65
Supramolecule | Name: Complex of Human Complement C3b and T. brucei ISG65 / type: complex / ID: 1 / Parent: 0 / Macromolecule list: all |
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Molecular weight | Theoretical: 44.2 KDa |
-Supramolecule #2: Human Complement C3b
Supramolecule | Name: Human Complement C3b / type: complex / ID: 2 / Parent: 1 / Macromolecule list: #1-#2 Details: C3 purified from human serum, C3b generated from C3 by limited trypsin proteolysis. |
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Source (natural) | Organism: Homo sapiens (human) / Tissue: Blood |
-Supramolecule #3: Trypanosoma brucei ISG65
Supramolecule | Name: Trypanosoma brucei ISG65 / type: complex / ID: 3 / Parent: 1 / Macromolecule list: #3 |
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Source (natural) | Organism: Trypanosoma brucei brucei (eukaryote) |
-Macromolecule #1: Complement C3f fragment
Macromolecule | Name: Complement C3f fragment / type: protein_or_peptide / ID: 1 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: Homo sapiens (human) / Tissue: Blood |
Molecular weight | Theoretical: 71.154047 KDa |
Sequence | String: SPMYSIITPN ILRLESEETM VLEAHDAQGD VPVTVTVHDF PGKKLVLSSE KTVLTPATNH MGNVTFTIPA NREFKSEKGR NKFVTVQAT FGTQVVEKVV LVSLQSGYLF IQTDKTIYTP GSTVLYRIFT VNHKLLPVGR TVMVNIENPE GIPVKQDSLS S QNQLGVLP ...String: SPMYSIITPN ILRLESEETM VLEAHDAQGD VPVTVTVHDF PGKKLVLSSE KTVLTPATNH MGNVTFTIPA NREFKSEKGR NKFVTVQAT FGTQVVEKVV LVSLQSGYLF IQTDKTIYTP GSTVLYRIFT VNHKLLPVGR TVMVNIENPE GIPVKQDSLS S QNQLGVLP LSWDIPELVN MGQWKIRAYY ENSPQQVFST EFEVKEYVLP SFEVIVEPTE KFYYIYNEKG LEVTITARFL YG KKVEGTA FVIFGIQDGE QRISLPESLK RIPIEDGSGE VVLSRKVLLD GVQNPRAEDL VGKSLYVSAT VILHSGSDMV QAE RSGIPI VTSPYQIHFT KTPKYFKPGM PFDLMVFVTN PDGSPAYRVP VAVQGEDTVQ SLTQGDGVAK LSINTHPSQK PLSI TVRTK KQELSEAEQA TRTMQALPYS TVGNSNNYLH LSVLRTELRP GETLNVNFLL RMDRAHEAKI RYYTYLIMNK GRLLK AGRQ VREPGQDLVV LPLSITTDFI PSFRLVAYYT LIGASGQREV VADSVWVDVK DSCVGSLVVK SGQSEDRQPV PGQQMT LKI EGDHGARVVL VAVDKGVFVL NKKNKLTQSK IWDVVEKADI GCTPGSGKDY AGVFSDAGLT FTSSSGQQTA QRAELQC PQ UniProtKB: Complement C3 |
-Macromolecule #2: Complement C3
Macromolecule | Name: Complement C3 / type: protein_or_peptide / ID: 2 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: Homo sapiens (human) / Tissue: Blood |
Molecular weight | Theoretical: 104.073164 KDa |
Sequence | String: SNLDEDIIAE ENIVSRSEFP ESWLWNVEDL KEPPKNGIST KLMNIFLKDS ITTWEILAVS MSDKKGICVA DPFEVTVMQD FFIDLRLPY SVVRNEQVEI RAVLYNYRQN QELKVRVELL HNPAFCSLAT TKRRHQQTVT IPPKSSLSVP YVIVPLKTGL Q EVEVKAAV ...String: SNLDEDIIAE ENIVSRSEFP ESWLWNVEDL KEPPKNGIST KLMNIFLKDS ITTWEILAVS MSDKKGICVA DPFEVTVMQD FFIDLRLPY SVVRNEQVEI RAVLYNYRQN QELKVRVELL HNPAFCSLAT TKRRHQQTVT IPPKSSLSVP YVIVPLKTGL Q EVEVKAAV YHHFISDGVR KSLKVVPEGI RMNKTVAVRT LDPERLGREG VQKEDIPPAD LSDQVPDTES ETRILLQGTP VA QMTEDAV DAERLKHLIV TPSGCGEQNM IGMTPTVIAV HYLDETEQWE KFGLEKRQGA LELIKKGYTQ QLAFRQPSSA FAA FVKRAP STWLTAYVVK VFSLAVNLIA IDSQVLCGAV KWLILEKQKP DGVFQEDAPV IHQEMIGGLR NNNEKDMALT AFVL ISLQE AKDICEEQVN SLPGSITKAG DFLEANYMNL QRSYTVAIAG YALAQMGRLK GPLLNKFLTT AKDKNRWEDP GKQLY NVEA TSYALLALLQ LKDFDFVPPV VRWLNEQRYY GGGYGSTQAT FMVFQALAQY QKDAPDHQEL NLDVSLQLPS RSSKIT HRI HWESASLLRS EETKENEGFT VTAEGKGQGT LSVVTMYHAK AKDQLTCNKF DLKVTIKPAP ETEKRPQDAK NTMILEI CT RYRGDQDATM SILDISMMTG FAPDTDDLKQ LANGVDRYIS KYELDKAFSD RNTLIIYLDK VSHSEDDCLA FKVHQYFN V ELIQPGAVKV YAYYNLEESC TRFYHPEKED GKLNKLCRDE LCRCAEENCF IQKSDDKVTL EERLDKACEP GVDYVYKTR LVKVQLSNDF DEYIMAIEQT IKSGSDEVQV GQQRTFISPI KCREALKLEE KKHYLMWGLS SDFWGEKPNL SYIIGKDTWV EHWPEEDEC QDEENQKQCQ DLGAFTESMV VFGCPN UniProtKB: Complement C3 |
-Macromolecule #3: ISG65 G
Macromolecule | Name: ISG65 G / type: protein_or_peptide / ID: 3 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: Trypanosoma brucei brucei (eukaryote) |
Molecular weight | Theoretical: 32.597322 KDa |
Recombinant expression | Organism: Homo sapiens (human) |
Sequence | String: DNRVPGDKNL TKEGAAALCK MKHLADKVAE KRSQELKDRT QNFAGYIEFE LYRIDYWLEK LNGPKGRKDG YAKLSDSDIE KVKEIFDKA KDGIAKQLPE AKKAGEDAEK LHTEVKEAAA NARGQDLDDH KQKSTGLYRV LNWYCITKEE SHNATPNCDG I QFRNHYLS ...String: DNRVPGDKNL TKEGAAALCK MKHLADKVAE KRSQELKDRT QNFAGYIEFE LYRIDYWLEK LNGPKGRKDG YAKLSDSDIE KVKEIFDKA KDGIAKQLPE AKKAGEDAEK LHTEVKEAAA NARGQDLDDH KQKSTGLYRV LNWYCITKEE SHNATPNCDG I QFRNHYLS VNRSAIDCSS TGYEENYDWS ANALQVALNS WENVKPKKLE SAGSDENCNI GQSSESHPCT MTEEWQTHYK ET VKKLKEL EGAHEKGRRA HDAMLGYANT AYAVNTKVEQ EKPLAEVIAA AK UniProtKB: ISG65 G |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Concentration | 2.2 mg/mL | |||||||||
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Buffer | pH: 7.4 Component:
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Grid | Model: Quantifoil R1.2/1.3 / Material: GOLD / Mesh: 300 / Support film - Material: CARBON / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 60 sec. / Pretreatment - Atmosphere: AIR | |||||||||
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 278.15 K / Instrument: FEI VITROBOT MARK IV |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Specialist optics | Energy filter - Name: GIF Quantum LS / Energy filter - Slit width: 20 eV |
Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number grids imaged: 1 / Number real images: 14339 / Average exposure time: 3.03 sec. / Average electron dose: 49.9 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 3.0 µm / Nominal defocus min: 1.0 µm |
Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |