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 (Ki = 480 μM) and N-methyl-N-glycolyl amide (Ki = 320 μM) glucosamine derivatives. A chemoenzymatic synthesis of an N-thioglycolyl amide PNAG pentasaccharide led to an inhibitor with an improved Ki of 280 μM.
许多在医学上具有重要意义的
生物膜形成细菌会产生类似的
多糖细胞间粘附素(
PIA),由部分去
N-乙酰化的 β-(1 → 6)-
N-乙酰
葡糖胺聚合物(d
PNAG)组成。在大肠杆菌中,β-(1→6)-
N-乙酰
葡糖胺聚合物(
PNAG)的去
N-乙酰化作用是由
碳水化合物酯酶家族 4 的
去乙酰化酶 PgaB 催化的。
PNAG 的去
N-乙酰化是
PNAG 依赖性
生物膜形成的关键。在此,我们介绍了用于体外监测 PgaB 活性的荧光测定法的开发以及一系列 PgaB
抑制剂的合成。合成的
抑制剂由
氨基葡萄糖支架上的
金属螯合官能团组成,靶向 PgaB 的活性位点
金属离子。N-thioglycolyl amide(Ki = 480 μM)和 N-methyl-N-glycolyl amide(Ki = 320 μM)
葡糖胺衍
生物的抑制效果最佳。通过
化学酶法合成 N-
硫代甘
氨酰
酰胺 PNAG 五糖,得到了一种 Ki 值为 280 μM 的
抑制剂。