+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-16795 | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Title | Cryo-EM structure of pentameric proteorhodopsin A18L mutant | |||||||||
Map data | ||||||||||
Sample |
| |||||||||
Keywords | Membrane protein / Light-driven proton pump / Proteorhodopsin / PROTON TRANSPORT | |||||||||
Function / homology | Function and homology information light-activated monoatomic ion channel activity / photoreceptor activity / phototransduction / plasma membrane Similarity search - Function | |||||||||
Biological species | uncultured Gammaproteobacteria bacterium (environmental samples) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.82 Å | |||||||||
Authors | Hirschi S / Lemmin T / Fotiadis D | |||||||||
Funding support | Switzerland, 1 items
| |||||||||
Citation | Journal: Nat Commun / Year: 2024 Title: Structural insights into the mechanism and dynamics of proteorhodopsin biogenesis and retinal scavenging. Authors: Stephan Hirschi / Thomas Lemmin / Nooraldeen Ayoub / David Kalbermatter / Daniele Pellegata / Zöhre Ucurum / Jürg Gertsch / Dimitrios Fotiadis / Abstract: Microbial ion-pumping rhodopsins (MRs) are extensively studied retinal-binding membrane proteins. However, their biogenesis, including oligomerisation and retinal incorporation, remains poorly ...Microbial ion-pumping rhodopsins (MRs) are extensively studied retinal-binding membrane proteins. However, their biogenesis, including oligomerisation and retinal incorporation, remains poorly understood. The bacterial green-light absorbing proton pump proteorhodopsin (GPR) has emerged as a model protein for MRs and is used here to address these open questions using cryo-electron microscopy (cryo-EM) and molecular dynamics (MD) simulations. Specifically, conflicting studies regarding GPR stoichiometry reported pentamer and hexamer mixtures without providing possible assembly mechanisms. We report the pentameric and hexameric cryo-EM structures of a GPR mutant, uncovering the role of the unprocessed N-terminal signal peptide in the assembly of hexameric GPR. Furthermore, certain proteorhodopsin-expressing bacteria lack retinal biosynthesis pathways, suggesting that they scavenge the cofactor from their environment. We shed light on this hypothesis by solving the cryo-EM structure of retinal-free proteoopsin, which together with mass spectrometry and MD simulations suggests that decanoate serves as a temporary placeholder for retinal in the chromophore binding pocket. Further MD simulations elucidate possible pathways for the exchange of decanoate and retinal, offering a mechanism for retinal scavenging. Collectively, our findings provide insights into the biogenesis of MRs, including their oligomeric assembly, variations in protomer stoichiometry and retinal incorporation through a potential cofactor scavenging mechanism. | |||||||||
History |
|
-Structure visualization
Supplemental images |
---|
-Downloads & links
-EMDB archive
Map data | emd_16795.map.gz | 20.9 MB | EMDB map data format | |
---|---|---|---|---|
Header (meta data) | emd-16795-v30.xml emd-16795.xml | 14.4 KB 14.4 KB | Display Display | EMDB header |
Images | emd_16795.png | 210.8 KB | ||
Filedesc metadata | emd-16795.cif.gz | 5.4 KB | ||
Others | emd_16795_half_map_1.map.gz emd_16795_half_map_2.map.gz | 20.4 MB 20.4 MB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-16795 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-16795 | HTTPS FTP |
-Validation report
Summary document | emd_16795_validation.pdf.gz | 738.5 KB | Display | EMDB validaton report |
---|---|---|---|---|
Full document | emd_16795_full_validation.pdf.gz | 738.1 KB | Display | |
Data in XML | emd_16795_validation.xml.gz | 10.4 KB | Display | |
Data in CIF | emd_16795_validation.cif.gz | 12.1 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-16795 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-16795 | HTTPS FTP |
-Related structure data
Related structure data | 8cqcMC 8cnkC 8cqdC M: atomic model generated by this map C: citing same article (ref.) |
---|---|
Similar structure data | Similarity search - Function & homologyF&H Search |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
---|---|
Related items in Molecule of the Month |
-Map
File | Download / File: emd_16795.map.gz / Format: CCP4 / Size: 22.2 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.0047 Å | ||||||||||||||||||||||||||||||||||||
Density |
| ||||||||||||||||||||||||||||||||||||
Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
|
-Supplemental data
-Half map: #2
File | emd_16795_half_map_1.map | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Projections & Slices |
| ||||||||||||
Density Histograms |
-Half map: #1
File | emd_16795_half_map_2.map | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Projections & Slices |
| ||||||||||||
Density Histograms |
-Sample components
-Entire : Pentameric proteorhodopsin A18L
Entire | Name: Pentameric proteorhodopsin A18L |
---|---|
Components |
|
-Supramolecule #1: Pentameric proteorhodopsin A18L
Supramolecule | Name: Pentameric proteorhodopsin A18L / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
---|---|
Source (natural) | Organism: uncultured Gammaproteobacteria bacterium (environmental samples) |
-Macromolecule #1: Green-light absorbing proteorhodopsin
Macromolecule | Name: Green-light absorbing proteorhodopsin / type: protein_or_peptide / ID: 1 / Number of copies: 5 / Enantiomer: LEVO |
---|---|
Source (natural) | Organism: uncultured Gammaproteobacteria bacterium (environmental samples) |
Molecular weight | Theoretical: 28.110854 KDa |
Recombinant expression | Organism: Escherichia coli (E. coli) |
Sequence | String: MGKLLLILGS VIALPTFLAG GGDLDASDYT GVSFWLVTAA LLASTVFFFV ERDRVSAKWK TSLTVSGLVT GIAFWHYMYM RGVWIETGD SPTVFRYIDW LLTVPLLICE FYLILAAATN VAGSLFKKLL VGSLVMLVFG YMGEAGIMAA WPAFIIGCLA W VYMIYELW ...String: MGKLLLILGS VIALPTFLAG GGDLDASDYT GVSFWLVTAA LLASTVFFFV ERDRVSAKWK TSLTVSGLVT GIAFWHYMYM RGVWIETGD SPTVFRYIDW LLTVPLLICE FYLILAAATN VAGSLFKKLL VGSLVMLVFG YMGEAGIMAA WPAFIIGCLA W VYMIYELW AGEGKSACNT ASPAVQSAYN TMMYIIIFGW AIYPVGYFTG YLMGDGGSAL NLNLIYNLAD FVNKILFGLI IW NVAVKES SNAGHHHHH UniProtKB: Green-light absorbing proteorhodopsin |
-Macromolecule #2: RETINAL
Macromolecule | Name: RETINAL / type: ligand / ID: 2 / Number of copies: 5 / Formula: RET |
---|---|
Molecular weight | Theoretical: 284.436 Da |
Chemical component information | ChemComp-RET: |
-Macromolecule #3: water
Macromolecule | Name: water / type: ligand / ID: 3 / Number of copies: 30 / Formula: HOH |
---|---|
Molecular weight | Theoretical: 18.015 Da |
Chemical component information | ChemComp-HOH: |
-Experimental details
-Structure determination
Method | cryo EM |
---|---|
Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Concentration | 4.2 mg/mL |
---|---|
Buffer | pH: 7.5 |
Vitrification | Cryogen name: ETHANE / Instrument: FEI VITROBOT MARK IV |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
---|---|
Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 49.8 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: OTHER / Imaging mode: BRIGHT FIELD / Nominal defocus max: 1.7 µm / Nominal defocus min: 0.7000000000000001 µm / Nominal magnification: 105000 |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
-Image processing
Startup model | Type of model: NONE |
---|---|
Final reconstruction | Applied symmetry - Point group: C5 (5 fold cyclic) / Resolution.type: BY AUTHOR / Resolution: 2.82 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: cryoSPARC / Number images used: 709759 |
Initial angle assignment | Type: ANGULAR RECONSTITUTION |
Final angle assignment | Type: ANGULAR RECONSTITUTION |