Capillary electrophoresis as a fragment screening tool to cross-validate hits from chromogenic assay: Application to FXIIa

Coumarins as factor XIIa inhibitors: Potency and selectivity improvements using a fragment-based strategy

Previously, we described weak coumarin inhibitors of factor XIIa, a promising target for artificial surface-induced thrombosis and various inflammatory diseases. In this work, we used fragment-based drug discovery approach to improve our coumarin series. First, we screened about 200 fragments for the S1 pocket. The S1 pocket of trypsin-like serine proteases, such as factor XIIa, is highly conserved and is known to drive a major part of the association energy. From the screening, we selected fragments displaying a micromolar activity and studied their selectivity on other serine proteases. Then, these fragments were merged to our coumarin templates, leading to the generation of nanomolar inhibitors. The mechanism of inhibition was further studied by mass spectrometry demonstrating the covalent binding through the formation of an acyl enzyme complex. The most potent compound was tested in plasma to evaluate its stability and efficacy on coagulation assays. It exhibited a plasmatic half-life of 1.9 h and a good selectivity for the intrinsic coagulation pathway over the extrinsic one.

Fragment-to-Lead Medicinal Chemistry Publications in 2021

This Perspective is the seventh in an annual series that summarizes successful Fragment-to-Lead (F2L) case studies published in a given year. A tabulated summary of relevant articles published in 2021 is provided, and features such as target class, screening methods, and ligand efficiency are discussed, both for the 2021 examples and for the combined examples over the years 2015-2021. In addition, trends and new developments in the field are summarized. In particular, the use of structural information in fragment-based drug discovery is discussed.

Fragment Hit Discovery and Binding Site Characterization by Indirect Affinity Capillary Electrophoresis: Application to Factor XIIa

Fragment-based lead discovery is a usual strategy in drug discovery to identify innovative lead compounds. The success of this approach strongly relies on the capacity to detect weak binders and characterize their binding site. NMR and X-ray crystallography are the conventional technologies used to tackle this challenge. However, their large protein consumption and the cost of equipment reduce their accessibility. Here, an affinity capillary electrophoresis methodology was developed that enables the detection of mM binders, the determination of dissociation constants, and the characterization of the fragment binding site. On the basis of multiple equilibrium theory, dissociation constants in the μM-mM range were determined, and a new methodology is proposed to establish graphically if two fragments bind the same protein pocket. The applicability of this methodology was demonstrated experimentally on coagulation factor XIIa by evaluating pairs of fragments with expected behavior. This study reinforces the significance of using affinity capillary electrophoresis to gather valuable information for medicinal chemistry projects.