ABSTRACT
Heparanase (HPA) is a critical enzyme involved in the remodeling of the extracellular matrix (ECM), and its elevated expression has been linked with diseases such as various types of cancer and inflammation. The detection of heparanase enzymatic activity holds tremendous value in the study of the cellular microenvironment, and search of molecular therapeutics targeting heparanase, however, no structurally defined probes are available for the detection of heparanase activity. Here we present the development of the first ultrasensitive fluorogenic small-molecule probe for heparanase enzymatic activity via tuning the electronic effect of the substrate. The probe exhibits a 756-fold fluorescence turn-on response in the presence of human heparanase, allowing one-step detection of heparanase activity in real-time with a picomolar detection limit. The high sensitivity and robustness of the probe are exemplified in a high-throughput screening assay for heparanase inhibitors.
ABSTRACT
The Escherichia coli siderophore enterobactin is assembled from 2,3-dihydroxybenzoate (2,3-DHB) and l-serine by the nonribosomal peptide synthetases EntB and EntF. The processive thiol-template strategy used can be sabotaged by EntB misacylation. Through in vitro kinetic analysis, we demonstrate two potential routes to EntB misacylation and provide evidence for two mechanisms by which the hot dog-fold thioesterase EntH can potentially prevent or reverse EntB misacylation.
