Mannose-specific adhesion of E. coli bacteria to their host cells is mediated by so-called type 1 fimbriae containing lectin domains present on the type 1 fimbrial FimH protein. The crystal structure of a FimH-FimC(chaperone) protein complex revealed a number of amino acids in the carbohydrate binding site with aromatic side chains. This finding is in keeping with earlier results showing high inhibitory potencies of aryl mannosides when tested as inhibitors of type 1 fimbriae-mediated bacterial adhesion. In addition, clustering of mannosyl moieties also led to favourable effects, as in the case of trivalent cluster mannosides such as (1). In order to combine both, i.e. the clustering approach and the advantage of an aromatic moiety, the herein presented study has emphasized the synthesis of three cluster mannosides (2), (3), and (4), as ligands for the type 1 fimbrial lectin, which contain a phenyl partial structure in different proximity to the core of the molecule. The inhibitory potencies of the new cluster mannosides were determined in enzyme-linked immunosorbent assays (ELISAs).
大肠杆菌细菌对宿主细胞的甘霖特异性粘附是通过所谓的含有凝集素结构域的1型纤毛介导的,这些凝集素结构域存在于1型纤毛FimH蛋白上。FimH-FimC(分子伴侣)蛋白复合物的晶体结构揭示了在糖类结合位点中具有芳香侧链的多个氨基酸。这一发现与早期结果一致,显示芳基甘霖苷在作为1型纤毛介导的细菌粘附抑制剂时具有较高的抑制效力。此外,甘霖基团的聚集也导致了有利效果,如三价簇甘霖苷的情况。为了结合聚集方法和芳香基团的优势,本研究强调了合成三种簇甘霖苷(2)、(3)和(4),作为1型纤毛凝集素的配体,这些配体在分子核心附近具有不同距离的苯基部分结构。新簇甘霖苷的抑制效力是通过酶联免疫吸附测定(ELISA)确定的。