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Title | HIV-1 Intasomes Assembled with Excess Integrase C-Terminal Domain Protein Facilitate Structural Studies by Cryo-EM and Reveal the Role of the Integrase C-Terminal Tail in HIV-1 Integration. |
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Journal, issue, pages | Viruses, Vol. 16, Issue 7, Year 2024 |
Publish date | Jul 20, 2024 |
Authors | Min Li / Zhen Li / Xuemin Chen / Yanxiang Cui / Alan N Engelman / Robert Craigie / |
PubMed Abstract | Retroviral integration is mediated by intasome nucleoprotein complexes wherein a pair of viral DNA ends are bridged together by a multimer of integrase (IN). Atomic-resolution structures of HIV-1 ...Retroviral integration is mediated by intasome nucleoprotein complexes wherein a pair of viral DNA ends are bridged together by a multimer of integrase (IN). Atomic-resolution structures of HIV-1 intasomes provide detailed insights into the mechanism of integration and inhibition by clinical IN inhibitors. However, previously described HIV-1 intasomes are highly heterogeneous and have the tendency to form stacks, which is a limiting factor in determining high-resolution cryo-EM maps. We have assembled HIV-1 intasomes in the presence of excess IN C-terminal domain protein, which was readily incorporated into the intasomes. The purified intasomes were largely homogeneous and exhibited minimal stacking tendencies. The cryo-EM map resolution was further improved to 2.01 Å, which will greatly facilitate structural studies of IN inhibitor action and drug resistance mechanisms. The C-terminal 18 residues of HIV-1 IN, which are critical for virus replication and integration in vitro, have not been well resolved in previous intasome structures, and its function remains unclear. We show that the C-terminal tail participates in intasome assembly, resides within the intasome core, and forms a small alpha helix (residues 271-276). Mutations that disrupt alpha helix integrity impede IN activity in vitro and disrupt HIV-1 infection at the step of viral DNA integration. |
External links | Viruses / PubMed:39066328 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.01 Å |
Structure data | EMDB-45364, PDB-9c9m: |
Chemicals | ChemComp-MG: ChemComp-ZN: ChemComp-DLU: ChemComp-HOH: |
Source |
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Keywords | VIRAL PROTEIN / HIV-1 / integrase / nucleoprotein complexes / INSTI / intasome / CryoEM |