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Open data
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Basic information
Entry | ![]() | |||||||||
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Title | HK97 Portal Protein In situ (prohead II) | |||||||||
![]() | HK97 bacteriophage portal protein in prohead II as part of packaging complex. Symmetry = C12. | |||||||||
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![]() | portal / HK97 / bacteriophage / packaging / VIRAL PROTEIN | |||||||||
Function / homology | Phage portal protein, HK97 / Bacteriophage/Gene transfer agent portal protein / Phage portal protein / viral capsid / Portal protein![]() | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.97 Å | |||||||||
![]() | Hawkins DEDP / Antson AA | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Insights into a viral motor: the structure of the HK97 packaging termination assembly. Authors: Dorothy E D P Hawkins / Oliver W Bayfield / Herman K H Fung / Daniel N Grba / Alexis Huet / James F Conway / Alfred A Antson / ![]() ![]() ![]() Abstract: Double-stranded DNA viruses utilise machinery, made of terminase proteins, to package viral DNA into the capsid. For cos bacteriophage, a defined signal, recognised by small terminase, flanks each ...Double-stranded DNA viruses utilise machinery, made of terminase proteins, to package viral DNA into the capsid. For cos bacteriophage, a defined signal, recognised by small terminase, flanks each genome unit. Here we present the first structural data for a cos virus DNA packaging motor, assembled from the bacteriophage HK97 terminase proteins, procapsids encompassing the portal protein, and DNA containing a cos site. The cryo-EM structure is consistent with the packaging termination state adopted after DNA cleavage, with DNA density within the large terminase assembly ending abruptly at the portal protein entrance. Retention of the large terminase complex after cleavage of the short DNA substrate suggests that motor dissociation from the capsid requires headful pressure, in common with pac viruses. Interestingly, the clip domain of the 12-subunit portal protein does not adhere to C12 symmetry, indicating asymmetry induced by binding of the large terminase/DNA. The motor assembly is also highly asymmetric, showing a ring of 5 large terminase monomers, tilted against the portal. Variable degrees of extension between N- and C-terminal domains of individual subunits suggest a mechanism of DNA translocation driven by inter-domain contraction and relaxation. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 116.9 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 16.1 KB 16.1 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() ![]() | 11.3 KB 14.6 KB | Display Display | ![]() |
Images | ![]() | 68.6 KB | ||
Masks | ![]() | 125 MB | ![]() | |
Filedesc metadata | ![]() | 6.1 KB | ||
Others | ![]() ![]() | 98.1 MB 98.1 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8cezMC ![]() 8cfaC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Map
File | ![]() | ||||||||||||||||||||
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Annotation | HK97 bacteriophage portal protein in prohead II as part of packaging complex. Symmetry = C12. | ||||||||||||||||||||
Voxel size | X=Y=Z: 1.34 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Mask #1
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Projections & Slices |
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Density Histograms |
-Half map: HK97 bacteriophage portal protein in prohead II as...
File | emd_16614_half_map_1.map | ||||||||||||
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Annotation | HK97 bacteriophage portal protein in prohead II as part of packaging complex. Symmetry = C12. | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: HK97 bacteriophage portal protein in prohead II as...
File | emd_16614_half_map_2.map | ||||||||||||
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Annotation | HK97 bacteriophage portal protein in prohead II as part of packaging complex. Symmetry = C12. | ||||||||||||
Projections & Slices |
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Density Histograms |
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Sample components
-Entire : Hendrixvirus
Entire | Name: ![]() |
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Components |
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-Supramolecule #1: Hendrixvirus
Supramolecule | Name: Hendrixvirus / type: virus / ID: 1 / Parent: 0 / Macromolecule list: all Details: Proheads were produced by infection of E. coli 594 cells with HK97 amber mutant amC2, propagated using Escherichia LE392 cells. NCBI-ID: 2169654 / Sci species name: Hendrixvirus / Sci species strain: HK97 / Virus type: VIRION / Virus isolate: STRAIN / Virus enveloped: No / Virus empty: No |
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Host (natural) | Organism: ![]() |
Molecular weight | Theoretical: 560 KDa |
-Macromolecule #1: Portal protein
Macromolecule | Name: Portal protein / type: protein_or_peptide / ID: 1 / Number of copies: 12 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 47.318488 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: MEEPKYTIDL RTNNGWWARL KSWFVGGRLV TPNQGSQTGP VSAHGYLGDS SINDERILQI STVWRCVSLI STLTACLPLD VFETDQNDN RKKVDLSNPL ARLLRYSPNQ YMTAQEFREA MTMQLCFYGN AYALVDRNSA GDVISLLPLQ SANMDVKLVG K KVVYRYQR ...String: MEEPKYTIDL RTNNGWWARL KSWFVGGRLV TPNQGSQTGP VSAHGYLGDS SINDERILQI STVWRCVSLI STLTACLPLD VFETDQNDN RKKVDLSNPL ARLLRYSPNQ YMTAQEFREA MTMQLCFYGN AYALVDRNSA GDVISLLPLQ SANMDVKLVG K KVVYRYQR DSEYADFSQK EIFHLKGFGF TGLVGLSPIA FACKSAGVAV AMEDQQRDFF ANGAKSPQIL STGEKVLTEQ QR SQVEENF KEIAGGPVKK RLWILEAGFS TSAIGVTPQD AEMMASRKFQ VSELARFFGV PPHLVGDVEK STSWGSGIEQ QNL GFLQYT LQPYISRWEN SIQRWLIPSK DVGRLHAEHN LDGLLRGDSA SRAAFMKAMG ESGLRTINEM RRTDNMPPLP GGDV AMRQA QYVPITDLGT NKEPRNNGA UniProtKB: Portal protein |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 7.5 Details: final buffer = 20 mM Tris pH 7.5, 10 mM MgCl2, 50 mM KGlu, 5 mM ATP-gamma-S |
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Grid | Model: Quantifoil / Material: COPPER / Mesh: 200 / Support film - Material: CARBON / Support film - topology: CONTINUOUS / Support film - Film thickness: 0.2 / Pretreatment - Type: PLASMA CLEANING / Pretreatment - Time: 60 sec. |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 90 % / Instrument: FEI VITROBOT MARK IV |
Details | Packaging reactions 30 nM hk97 proheads, 2.5 micromolar large terminase, 5 micromolar small terminase and 30 nM DNA, 75 micromolar ATP were incubated for 2 mins then 5 micromolar ATP-gamma-S was added. |
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Electron microscopy
Microscope | TFS KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number grids imaged: 1 / Average electron dose: 40.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.5 µm / Nominal defocus min: 0.5 µm |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |