Download MendeleyAn unusual dimeric structure and assembly for TLR4 regulator RP105-MD-1.
Yoon, S.I., Hong, M., Wilson, I.A.(2011) Nat Struct Mol Biol 18: 1028-1035
- PubMed: 21857663
- DOI: https://doi.org/10.1038/nsmb.2106
- Primary Citation of Related Structures:
3RG1 - PubMed Abstract:
RP105-MD-1 modulates the TLR4-MD-2-mediated, innate immune response against bacterial lipopolysaccharide (LPS). The crystal structure of the bovine 1:1 RP105-MD-1 complex bound to a putative endogenous lipid at 2.9 Å resolution shares a similar overall architecture to its homolog TLR4-MD-2 but assembles into an unusual 2:2 homodimer that differs from any other known TLR-ligand assembly. The homodimer is assembled in a head-to-head orientation that juxtaposes the N-terminal leucine-rich repeats (LRRs) of the two RP105 chains, rather than the usual tail-to-tail configuration of C-terminal LRRs in ligand-activated TLR dimers, such as TLR1-TRL2, TLR2-TLR6, TLR3-TLR3 and TLR4-TLR4. Another unusual interaction is mediated by an RP105-specific asparagine-linked glycan, which wedges MD-1 into the co-receptor binding concavity on RP105. This unique mode of assembly represents a new paradigm for TLR complexes and suggests a molecular mechanism for regulating LPS responses.
Organizational Affiliation:
Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
