Toll-like receptor 2 (TLR2), a member of the TLR innate immune receptor family, recognizes lipoproteins from bacteria and modulates the immune response by inducing the expression of various cytokines. TLR2 has a large hydrophobic pocket that recognizes long fatty acyl groups on TLR2 ligands. However, few studies have focused on the property of the hydrophobic TLR2 pocket. Based on the X-ray crystal structure of TLR2, small polar regions were found in the hydrophobic TLR2 pocket. Interactions between the polar residues and ligands were explored here by designing and synthesizing a Pam₂CSK₄ derivative of the TLR2 ligands, containing an amide group within the lipid moiety. We evaluated the binding affinities and immunomodulatory activities of these ligands. Results suggested that the amide groups in the lipid chain interacted with the polar residues in the hydrophobic lipid-binding pocket of TLR2.

Toll样受体2（TLR2）是TLR先天性免疫受体家族的成员，它能够识别细菌中的脂蛋白并通过诱导各种细胞因子的表达来调节免疫反应。TLR2有一个大的疏水口袋，可识别TLR2配体上的长脂肪酰基。然而，很少有研究集中在疏水性TLR2袋的性质上。基于TLR2的X射线晶体结构，在疏水性TLR2的口袋中发现了小的极性区域。通过设计和合成Pam ₂ CSK ₄，探索了极性残基与配体之间的相互作用。TLR2配体的衍生物，在脂质部分包含一个酰胺基。我们评估了这些配体的结合亲和力和免疫调节活性。结果表明脂质链中的酰胺基团与TLR2疏水脂质结合口袋中的极性残基相互作用。