Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
Org Biomol Chem. 2012 Sep 21;10(35):7103-7. doi: 10.1039/c2ob26105g. Epub 2012 Aug 2.
Many medically important biofilm forming bacteria produce similar polysaccharide intercellular adhesins (PIA) consisting of partially de-N-acetylated β-(1 → 6)-N-acetylglucosamine polymers (dPNAG). In Escherichia coli, de-N-acetylation of the β-(1 → 6)-N-acetylglucosamine polymer (PNAG) is catalysed by the carbohydrate esterase family 4 deacetylase PgaB. The de-N-acetylation of PNAG is essential for productive PNAG-dependent biofilm formation. Here, we describe the development of a fluorogenic assay to monitor PgaB activity in vitro and the synthesis of a series of PgaB inhibitors. The synthesized inhibitors consist of a metal chelating functional group on a glucosamine scaffold to target the active site metal ion of PgaB. Optimal inhibition was observed with N-thioglycolyl amide (K(i) = 480 μM) and N-methyl-N-glycolyl amide (K(i) = 320 μM) glucosamine derivatives. A chemoenzymatic synthesis of an N-thioglycolyl amide PNAG pentasaccharide led to an inhibitor with an improved K(i) of 280 μM.
许多具有医学重要性的生物膜形成细菌产生相似的多糖细胞间黏附素（PIA），由部分去 N-乙酰化的β-（1→6）-N-乙酰葡萄糖胺聚合物（dPNAG）组成。在大肠杆菌中，β-（1→6）-N-乙酰葡萄糖胺聚合物（PNAG）的去 N-乙酰化作用由碳水化合物酯酶家族 4 脱乙酰酶 PgaB 催化。PNAG 的去 N-乙酰化作用对于生产性的 PNAG 依赖性生物膜形成是必不可少的。在这里，我们描述了一种荧光测定法的开发，用于体外监测 PgaB 的活性，以及一系列 PgaB 抑制剂的合成。合成的抑制剂由葡萄糖胺支架上的金属螯合功能基团组成，以针对 PgaB 的活性部位金属离子。用 N-硫代甘氨酰酰胺（K(i) = 480 μM）和 N-甲基-N-甘氨酰酰胺（K(i) = 320 μM）葡萄糖胺衍生物观察到最佳抑制作用。N-硫代甘氨酰酰胺 PNAG 五糖的化学酶合成导致抑制剂的 K(i)值提高到 280 μM。
