SNAP output for PDB entry 4z0c [SNAP web server]

PDB-id

4z0c; SNAP-derived features in text and JSON formats; DNAproDB

Class

immune system

Method

X-ray (2.3 Å)

Summary

Crystal structure of tlr13-ssrna13 complex

Reference

Song W, Wang J, Han Z, Zhang Y, Zhang H, Wang W, Chang J, Xia B, Fan S, Zhang D, Wang J, Wang HW, Chai J (2015): "Structural basis for specific recognition of single-stranded RNA by Toll-like receptor 13." Nat.Struct.Mol.Biol., 22, 782-787. doi: 10.1038/nsmb.3080.

Abstract

Toll-like receptors (TLRs) have crucial roles in innate immunity, functioning as pattern-recognition receptors. TLR13 recognizes a conserved sequence from bacterial 23S rRNA and then triggers an immune response. Here we report the crystal structure of the mouse TLR13 ectodomain bound by a 13-nt single-stranded (ss) RNA derived from 23S rRNA. The ssRNA induces TLR13 dimerization but assumes a stem-loop-like structure that is completely different from that in the bacterial ribosome but nevertheless is crucial for TLR13 recognition. Most of the RNA nucleotides are splayed out to make base-specific contacts with the concave surface of TLR13, and RNA-specific interactions are important to allow TLR13 to distinguish RNA from DNA. Interestingly, a viral-derived 16-nt ssRNA predicted to form a similar stem-loop-like structure also induces TLR13 activation. Together, our results reveal the structural mechanism of TLR13's sequence- and conformation-specific recognition of ssRNA.