5UDI

IFIT1 monomeric mutant (L457E/L464E) with m7Gppp-AAAA (syn and anti conformations of cap)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free: 0.178 
  • R-Value Work: 0.157 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure of human IFIT1 with capped RNA reveals adaptable mRNA binding and mechanisms for sensing N1 and N2 ribose 2'-O methylations.

Abbas, Y.M.Laudenbach, B.T.Martinez-Montero, S.Cencic, R.Habjan, M.Pichlmair, A.Damha, M.J.Pelletier, J.Nagar, B.

(2017) Proc. Natl. Acad. Sci. U.S.A. 114: E2106-E2115

  • DOI: 10.1073/pnas.1612444114
  • Primary Citation of Related Structures:  5UDJ, 5UDK, 5UDL

  • PubMed Abstract: 
  • IFIT1 (IFN-induced protein with tetratricopeptide repeats-1) is an effector of the host innate immune antiviral response that prevents propagation of virus infection by selectively inhibiting translation of viral mRNA. It relies on its ability to com ...

    IFIT1 (IFN-induced protein with tetratricopeptide repeats-1) is an effector of the host innate immune antiviral response that prevents propagation of virus infection by selectively inhibiting translation of viral mRNA. It relies on its ability to compete with the translation initiation factor eIF4F to specifically recognize foreign capped mRNAs, while remaining inactive against host mRNAs marked by ribose 2'-O methylation at the first cap-proximal nucleotide (N1). We report here several crystal structures of RNA-bound human IFIT1, including a 1.6-Å complex with capped RNA. IFIT1 forms a water-filled, positively charged RNA-binding tunnel with a separate hydrophobic extension that unexpectedly engages the cap in multiple conformations (syn and anti) giving rise to a relatively plastic and nonspecific mode of binding, in stark contrast to eIF4E. Cap-proximal nucleotides encircled by the tunnel provide affinity to compete with eIF4F while allowing IFIT1 to select against N1 methylated mRNA. Gel-shift binding assays confirm that N1 methylation interferes with IFIT1 binding, but in an RNA-dependent manner, whereas translation assays reveal that N1 methylation alone is not sufficient to prevent mRNA recognition at high IFIT1 concentrations. Structural and functional analysis show that 2'-O methylation at N2, another abundant mRNA modification, is also detrimental for RNA binding, thus revealing a potentially synergistic role for it in self- versus nonself-mRNA discernment. Finally, structure-guided mutational analysis confirms the importance of RNA binding for IFIT1 restriction of a human coronavirus mutant lacking viral N1 methylation. Our structural and biochemical analysis sheds new light on the molecular basis for IFIT1 translational inhibition of capped viral RNA.


    Organizational Affiliation

    Department of Biochemistry and Groupe de Recherche Axe sur la Structure des Proteines, McGill University, Montreal, QC, Canada H3G 0B1.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Interferon-induced protein with tetratricopeptide repeats 1
A
479Homo sapiensGene Names: IFIT1 (G10P1, IFI56, IFNAI1, ISG56)
Find proteins for P09914 (Homo sapiens)
Go to Gene View: IFIT1
Go to UniProtKB:  P09914
Entity ID: 2
MoleculeChainsLengthOrganism
RNA (5'-D(*(GTA))-R(P*AP*AP*A)-3')B4unidentified
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
PGE
Query on PGE

Download SDF File 
Download CCD File 
A
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
GTA
Query on GTA
B
NON-POLYMERC21 H30 N10 O17 P3

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free: 0.178 
  • R-Value Work: 0.157 
  • Space Group: P 42 2 2
Unit Cell:
Length (Å)Angle (°)
a = 111.715α = 90.00
b = 111.715β = 90.00
c = 93.157γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PHASERphasing
HKL-2000data scaling
PDB_EXTRACTdata extraction
PHENIXrefinement
DENZOdata reduction
Cootmodel building

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationCountryGrant Number
Canadian Institutes of Health ResearchCanadaMOP-133535

Revision History 

  • Version 1.0: 2017-03-01
    Type: Initial release
  • Version 1.1: 2017-03-15
    Type: Database references
  • Version 1.2: 2017-03-22
    Type: Database references
  • Version 1.3: 2017-11-22
    Type: Refinement description