• Ho Min Kim, Beom Seok Park, Jung-In Kim, Sung Eun Kim, Judong Lee, Se Cheol Oh, Purevjav Enkhbayar, Norio Matsushima, Hayyoung Lee, Ook Joon Yoo, and Jie-Oh Lee.
• Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejon, Korea 305-701.
• Cell. 2007 Sep 7; 130 (5): 906-17.

AbstractTLR4 and MD-2 form a heterodimer that recognizes LPS (lipopolysaccharide) from Gram-negative bacteria. Eritoran is an analog of LPS that antagonizes its activity by binding to the TLR4-MD-2 complex. We determined the structure of the full-length ectodomain of the mouse TLR4 and MD-2 complex. We also produced a series of hybrids of human TLR4 and hagfish VLR and determined their structures with and without bound MD-2 and Eritoran. TLR4 is an atypical member of the LRR family and is composed of N-terminal, central, and C-terminal domains. The beta sheet of the central domain shows unusually small radii and large twist angles. MD-2 binds to the concave surface of the N-terminal and central domains. The interaction with Eritoran is mediated by a hydrophobic internal pocket in MD-2. Based on structural analysis and mutagenesis experiments on MD-2 and TLR4, we propose a model of TLR4-MD-2 dimerization induced by LPS.

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