2qfb

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Template:STRUCTURE 2qfb

Crystal structure of the regulatory domain of human RIG-I with bound Zn

Overview

The ATPase RIG-I senses viral RNAs that contain 5'-triphosphates in the cytoplasm. It initiates a signaling cascade that activates innate immune response by interferon and cytokine production, providing essential antiviral protection for the host. The mode of RNA 5'-triphosphate sensing by RIG-I remains elusive. We show that the C-terminal regulatory domain RD of RIG-I binds viral RNA in a 5'-triphosphate-dependent manner and activates the RIG-I ATPase by RNA-dependent dimerization. The crystal structure of RD reveals a zinc-binding domain that is structurally related to GDP/GTP exchange factors of Rab-like GTPases. The zinc coordination site is essential for RIG-I signaling and is also conserved in MDA5 and LGP2, suggesting related RD domains in all three enzymes. Structure-guided mutagenesis identifies a positively charged groove as likely 5'-triphosphate-binding site of RIG-I. This groove is distinct in MDA5 and LGP2, raising the possibility that RD confers ligand specificity.

About this Structure

2QFB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

The C-Terminal Regulatory Domain Is the RNA 5'-Triphosphate Sensor of RIG-I., Cui S, Eisenacher K, Kirchhofer A, Brzozka K, Lammens A, Lammens K, Fujita T, Conzelmann KK, Krug A, Hopfner KP, Mol Cell. 2008 Feb 1;29(2):169-179. PMID:18243112 Page seeded by OCA on Sun May 4 14:51:28 2008