De Leon Gladys P, Elowe Nadine H, Koteva Kalinka P, Valvano Miguel A, Wright Gerard D
Antimicrobial Research Centre, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada.
Chem Biol. 2006 Apr;13(4):437-41. doi: 10.1016/j.chembiol.2006.02.010.
The lipopolysaccharide (LPS)-rich outer membrane of gram-negative bacteria provides a protective barrier that insulates these organisms from the action of numerous antibiotics. Breach of the LPS layer can therefore provide access to the cell interior to otherwise impermeant toxic molecules and can expose vulnerable binding sites for immune system components such as complement. Inhibition of LPS biosynthesis, leading to a truncated LPS molecule, is an alternative strategy for antibacterial drug development in which this vital cellular structure is weakened. A significant challenge for in vitro screens of small molecules for inhibition of LPS biosynthesis is the difficulty in accessing the complex carbohydrate substrates. We have optimized an assay of the enzymes required for LPS heptose biosynthesis that simultaneously surveys five enzyme activities by using commercially available substrates and report its use in a small-molecule screen that identifies an inhibitor of heptose synthesis.
革兰氏阴性菌富含脂多糖（LPS）的外膜提供了一道保护屏障，使这些微生物免受多种抗生素的作用。因此，破坏LPS层可使原本无法渗透的有毒分子进入细胞内部，并可暴露补体等免疫系统成分的易受攻击的结合位点。抑制LPS生物合成，导致LPS分子截短，是抗菌药物开发的一种替代策略，在该策略中，这种重要的细胞结构被削弱。小分子体外筛选抑制LPS生物合成面临的一个重大挑战是难以获得复杂的碳水化合物底物。我们优化了一种LPS庚糖生物合成所需酶的测定方法，该方法通过使用市售底物同时检测五种酶活性，并报告其在小分子筛选中用于鉴定庚糖合成抑制剂的情况。
