PDBsum entry 4a2q

Hydrolase

PDB id: 4a2q

Contents

Protein chains

674 a.a.

PDB id:

4a2q

Name:

Hydrolase

Title:

Structure of duck rig-i tandem cards and helicase domain

Structure:

Retinoic acid inducible protein i. Chain: a, b, d, e. Fragment: tandem cards and helicase domain, residues 1-794. Synonym: rig-i. Engineered: yes

Source:

Anas platyrhynchos. Organism_taxid: 8839. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Expression_system_cell_line: high five.

Resolution:

3.40Å R-factor: 0.241 R-free: 0.276

Authors:

E.Kowalinski,T.Lunardi,A.A.Mccarthy,S.Cusack

Key ref:

E.Kowalinski et al. (2011). Structural basis for the activation of innate immune pattern-recognition receptor RIG-I by viral RNA. Cell, 147, 423-435. PubMed id: 22000019

Date:

28-Sep-11 Release date: 19-Oct-11

Protein chains

D3TI84  (D3TI84_ANAPL) -  RNA helicase from Anas platyrhynchos

Seq: 933 a.a.

Struc: 674 a.a.

Enzyme reactions

• Enzyme class: E.C.3.6.4.13 - Rna helicase.
• Reaction: ATP + H2O = ADP + phosphate + H⁺

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Cell 147:423-435 (2011)

PubMed id: 22000019

Structural basis for the activation of innate immune pattern-recognition receptor RIG-I by viral RNA.

E.Kowalinski, T.Lunardi, A.A.McCarthy, J.Louber, J.Brunel, B.Grigorov, D.Gerlier, S.Cusack.

ABSTRACT

RIG-I is a key innate immune pattern-recognition receptor that triggers interferon expression upon detection of intracellular 5'triphosphate double-stranded RNA (5'ppp-dsRNA) of viral origin. RIG-I comprises N-terminal caspase activation and recruitment domains (CARDs), a DECH helicase, and a C-terminal domain (CTD). We present crystal structures of the ligand-free, autorepressed, and RNA-bound, activated states of RIG-I. Inactive RIG-I has an open conformation with the CARDs sequestered by a helical domain inserted between the two helicase moieties. ATP and dsRNA binding induce a major rearrangement to a closed conformation in which the helicase and CTD bind the blunt end 5'ppp-dsRNA with perfect complementarity but incompatibly with continued CARD binding. We propose that after initial binding of 5'ppp-dsRNA to the flexibly linked CTD, co-operative tight binding of ATP and RNA to the helicase domain liberates the CARDs for downstream signaling. These findings significantly advance our molecular understanding of the activation of innate immune signaling helicases.