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Title | Crystal structure of human IPS-1/MAVS/VISA/Cardif caspase activation recruitment domain. |
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Journal, issue, pages | BMC Struct Biol, Vol. 8, Page 11, Year 2008 |
Publish date | Feb 28, 2008 |
![]() | Jane A Potter / Richard E Randall / Garry L Taylor / ![]() |
PubMed Abstract | BACKGROUND: IPS-1/MAVS/VISA/Cardif is an adaptor protein that plays a crucial role in the induction of interferons in response to viral infection. In the initial stage of the intracellular antiviral ...BACKGROUND: IPS-1/MAVS/VISA/Cardif is an adaptor protein that plays a crucial role in the induction of interferons in response to viral infection. In the initial stage of the intracellular antiviral response two RNA helicases, retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-association gene 5 (MDA5), are independently able to bind viral RNA in the cytoplasm. The 62 kDa protein IPS-1/MAVS/VISA/Cardif contains an N-terminal caspase activation and recruitment (CARD) domain that associates with the CARD regions of RIG-I and MDA5, ultimately leading to the induction of type I interferons. As a first step towards understanding the molecular basis of this important adaptor protein we have undertaken structural studies of the IPS-1 MAVS/VISA/Cardif CARD region. RESULTS: The crystal structure of human IPS-1/MAVS/VISA/Cardif CARD has been determined to 2.1A resolution. The protein was expressed and crystallized as a maltose-binding protein (MBP) fusion protein. The MBP and IPS-1 components each form a distinct domain within the structure. IPS-1/MAVS/VISA/Cardif CARD adopts a characteristic six-helix bundle with a Greek-key topology and, in common with a number of other known CARD structures, contains two major polar surfaces on opposite sides of the molecule. One face has a surface-exposed, disordered tryptophan residue that may explain the poor solubility of untagged expression constructs. CONCLUSION: The IPS-1/MAVS/VISA/Cardif CARD domain adopts the classic CARD fold with an asymmetric surface charge distribution that is typical of CARD domains involved in homotypic protein-protein interactions. The location of the two polar areas on IPS-1/MAVS/VISA/Cardif CARD suggest possible types of associations that this domain makes with the two CARD domains of MDA5 or RIG-I. The N-terminal CARD domains of RIG-I and MDA5 share greatest sequence similarity with IPS-1/MAVS/VISA/Cardif CARD and this has allowed modelling of their structures. These models show a very different charge profile for the equivalent surfaces compared to IPS-1/MAVS/VISA/Cardif CARD. |
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Methods | X-ray diffraction |
Resolution | 2.1 Å |
Structure data | ![]() PDB-2vgq: |
Chemicals | ![]() ChemComp-SO4: ![]() ChemComp-HOH: |
Source |
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![]() | IMMUNE SYSTEM/TRANSPORT / IPS1/MAVS/VISA/CARDIF / CASPASE ACTIVATION / CASPASE RECRUITMENT DOMAIN / INNATE IMMUNITY / FUSION PROTEIN / SUGAR TRANSPORT / TRANSPORT / IMMUNE SYSTEM / CHIMERA / IMMUNE SYSTEM-TRANSPORT complex |