Journal: Nature / Year: 2016 Title: Cryo-EM reveals a novel octameric integrase structure for betaretroviral intasome function. Authors: Allison Ballandras-Colas / Monica Brown / Nicola J Cook / Tamaria G Dewdney / Borries Demeler / Peter Cherepanov / Dmitry Lyumkis / Alan N Engelman / Abstract: Retroviral integrase catalyses the integration of viral DNA into host target DNA, which is an essential step in the life cycle of all retroviruses. Previous structural characterization of integrase- ...Retroviral integrase catalyses the integration of viral DNA into host target DNA, which is an essential step in the life cycle of all retroviruses. Previous structural characterization of integrase-viral DNA complexes, or intasomes, from the spumavirus prototype foamy virus revealed a functional integrase tetramer, and it is generally believed that intasomes derived from other retroviral genera use tetrameric integrase. However, the intasomes of orthoretroviruses, which include all known pathogenic species, have not been characterized structurally. Here, using single-particle cryo-electron microscopy and X-ray crystallography, we determine an unexpected octameric integrase architecture for the intasome of the betaretrovirus mouse mammary tumour virus. The structure is composed of two core integrase dimers, which interact with the viral DNA ends and structurally mimic the integrase tetramer of prototype foamy virus, and two flanking integrase dimers that engage the core structure via their integrase carboxy-terminal domains. Contrary to the belief that tetrameric integrase components are sufficient to catalyse integration, the flanking integrase dimers were necessary for mouse mammary tumour virus integrase activity. The integrase octamer solves a conundrum for betaretroviruses as well as alpharetroviruses by providing critical carboxy-terminal domains to the intasome core that cannot be provided in cis because of evolutionarily restrictive catalytic core domain-carboxy-terminal domain linker regions. The octameric architecture of the intasome of mouse mammary tumour virus provides new insight into the structural basis of retroviral DNA integration.
History
Deposition
Aug 26, 2015
-
Header (metadata) release
Sep 23, 2015
-
Map release
Feb 17, 2016
-
Update
Apr 13, 2016
-
Current status
Apr 13, 2016
Processing site: RCSB / Status: Released
-
Structure visualization
Movie
Surface view with section colored by density value
pH: 7.4 Details: 25 mM Tris-HCl, 200 mM NaCl, 2 mM DTT, 25 uM ZnCl2, 10 mM CaCl2
Grid
Details: 400 mesh C-flat, plasma-treated for 6 seconds
Vitrification
Cryogen name: ETHANE / Chamber humidity: 90 % / Chamber temperature: 77 K / Instrument: HOMEMADE PLUNGER Method: 3 uL of sample was applied to the grid, adsorbed for 30 seconds, blotted, and plunge-frozen in liquid ethane.
-
Electron microscopy
Microscope
FEI TITAN KRIOS
Alignment procedure
Legacy - Astigmatism: Objective lens astigmatism was corrected using Leginon, and coma-free alignment was established.
Date
Apr 15, 2016
Image recording
Category: CCD / Film or detector model: GATAN K2 (4k x 4k) / Number real images: 2714 / Average electron dose: 40 e/Å2
Electron beam
Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
Algorithm: OTHER / Resolution.type: BY AUTHOR / Resolution: 6.0 Å / Resolution method: OTHER / Software - Name: Frealign / Details: Local FSC values range from 5 to 6 Angstrom. / Number images used: 41475
Final angle assignment
Details: Frealign, phi, theta, psi
+
About Yorodumi
-
News
-
Feb 9, 2022. New format data for meta-information of EMDB entries
New format data for meta-information of EMDB entries
Version 3 of the EMDB header file is now the official format.
The previous official version 1.9 will be removed from the archive.
In the structure databanks used in Yorodumi, some data are registered as the other names, "COVID-19 virus" and "2019-nCoV". Here are the details of the virus and the list of structure data.
Jan 31, 2019. EMDB accession codes are about to change! (news from PDBe EMDB page)
EMDB accession codes are about to change! (news from PDBe EMDB page)
The allocation of 4 digits for EMDB accession codes will soon come to an end. Whilst these codes will remain in use, new EMDB accession codes will include an additional digit and will expand incrementally as the available range of codes is exhausted. The current 4-digit format prefixed with “EMD-” (i.e. EMD-XXXX) will advance to a 5-digit format (i.e. EMD-XXXXX), and so on. It is currently estimated that the 4-digit codes will be depleted around Spring 2019, at which point the 5-digit format will come into force.
The EM Navigator/Yorodumi systems omit the EMD- prefix.
Related info.:Q: What is EMD? / ID/Accession-code notation in Yorodumi/EM Navigator
Yorodumi is a browser for structure data from EMDB, PDB, SASBDB, etc.
This page is also the successor to EM Navigator detail page, and also detail information page/front-end page for Omokage search.
The word "yorodu" (or yorozu) is an old Japanese word meaning "ten thousand". "mi" (miru) is to see.
Related info.:EMDB / PDB / SASBDB / Comparison of 3 databanks / Yorodumi Search / Aug 31, 2016. New EM Navigator & Yorodumi / Yorodumi Papers / Jmol/JSmol / Function and homology information / Changes in new EM Navigator and Yorodumi