DPD-inspired discovery of novel LsrK kinase inhibitors: an opportunity to fight antimicrobial resistance

Antibiotic resistance is posing a continuous threat to global public health and represents a huge burden for society as a whole. In the past decade, the interference with bacterial quorum sensing (QS) (i.e., cell cell communication) mechanisms has extensively been investigated as a valid therapeutic approach in the pursuit of a next generation of antimicrobials. (S)-4,5-Dihydroxy-2,3-pentanedione, commonly known as (S)-DPD, a small signaling molecule that modulates QS in both Gram-negative and Gram-positive bacteria, is phosphorylated by LsrK, and the resulting phospho-DPD activates QS. We designed and prepared a small library of DPD derivatives, characterized by five different scaffolds, and evaluated their LsrK inhibition in the context of QS interference. SAR studies highlighted the pyrazole moiety as an essential structural element for LsrK inhibition. Particularly, four compounds were found to be micromolar LsrK inhibitors (IC50 ranging between 100 mu M and 500 mu M) encouraging further exploration of novel analogues as potential new antimicrobials.Peer reviewe

The European lead factory—an experiment in collaborative drug discovery

The European Lead Factory (ELF) is a unique collaborative public–private partnership aiming to deliver innovative drug discovery starting points and improving the value generated by ultra-High Throughput Screening (uHTS) approaches. Composed of a unique compound collection derived from private pharmaceutical company collections and complemented with new chemistries from a unique public collection, it offers a unique uHTS platform accessible to both private companies and publicly funded researchers. One of the key challenges in setting up ELF has been to balance access to screening results with protecting the value of compounds in the collection. Through an ‘honest data broker’ data management platform and a royalty reward scheme based on achieved milestones, ELF has been able to overcome these challenges. Set up in 2013, it has already accepted 42 targets for screening, submitted by publicly funded researchers, and generated 12 Qualified Hit Lists. In addition, 55,000 new library compounds have been generated by the public partners and added to the 320,000 compounds made available by the companies. Although it faced many challenges in becoming operational, this unique experiment in collaboration is already generating exciting results that will hopefully, eventually lead to better medicines and tools to advance our biological knowledge, and should act as a template for future approaches in the area

Fragment-Based Interrogation of the 14–3–3/TAZ Protein–Protein Interaction

The identification of chemical starting points for the development of molecular glues is challenging. Here, we employed fragment screening and identified an allosteric stabilizer of the complex between 14-3-3 and a TAZ-derived peptide. The fragment binds preferentially to the 14-3-3/TAZ peptide complex and shows moderate stabilization in differential scanning fluorimetry and microscale thermophoresis. The binding site of the fragment was predicted by molecular dynamics calculations to be distant from the 14-3-3/TAZ peptide interface, located between helices 8 and 9 of the 14-3-3 protein. This site was confirmed by nuclear magnetic resonance and X-ray protein crystallography, revealing the first example of an allosteric stabilizer for 14-3-3 protein-protein interactions

Expansion of chemical space for collaborative lead generation and drug discovery: the European Lead Factory Perspective

High-throughput screening (HTS) represents a major cornerstone of drug discovery. The availability of an innovative, relevant and high-quality compound collection to be screened often dictates the final fate of a drug discovery campaign. Given that the chemical space to be sampled in research programs is practically infinite and sparsely populated, significant efforts and resources need to be invested in the generation and maintenance of a competitive compound collection. The European Lead Factory (ELF) project is addressing this challenge by leveraging the diverse experience and know-how of academic groups and small and medium enterprises (SMEs) engaged in synthetic and/or medicinal chemistry. Here, we describe the novelty, diversity, structural complexity, physicochemical characteristics and overall attractiveness of this first batch of ELF compounds for HTS purposes

A characterization of psbO mutant genes encoding the 33 kDa protein in a cyanobacterium

This research was an attempt to characterize previously constructed mutants with a specifically altered psbO gene which encodes a 33 kDa protein active in photosynthesis. This polypeptide was believed to function in stabilization of manganese ions during photolysis of water at the photosystem II. The initial phase of this work was concerned with determining the manganese content of the genetically manipulated PS II particles of the photosynthetically active cyanobacteria.We found however, that the results of the isolation procedure for PS II particles of photosynthetically active cyanobacteria as described by Burnap et al. was not reproducible in our research organism. This prevented the chemical characterization of function of these particles as had been planned.In the second phase of the research sequencing of the mutated gene was to be performed for several clones in order to determine the kinds of specific alterations that had been made. The mutated genes had been cloned into both pUC1 20 and pPGV5 vectors which were transformed into Escherichia OR (EQQJi) and the cyanobacterium Synechococcus PCC 7942, respectively.Several attempts were mad o isolate plasmid DNA from both the transformed E QQJI and cyanobacterium. Isolation of pUC120 DNA was not achieved due to the toxicity of the 33 kDa protein product of the psbO gene in sgJj. The pPGV5 plasmid isolation was successful and PCR-sequencing was performed. However, the sequencing did not result in a readable sequence. Instead, banding patterns showed more than one nucleotide per lane. Since pPGV5 contains a strong constitutive promoter, a large amount of mutant protein was being produced. Our findings suggested that transformed cyanobacteria may have been under pressure to revert the altered gene to wild-type. Thus, upon growth of a single colony to a larger volume, a heterogeneous population of cells with different sizes of plasmids may have resulted. Restriction analysis of isolated plasmid DNA confirmed the presence of multiple-sized plasmid molecules. Therefore, this research has shown that the previously constructed mutants are not stable enough to characterize for alterations in manganese binding.Thesis (M.S.)Department of Biolog

Clinical candidates modulating protein-protein interactions: the fragment-based experience

Protein-protein interactions (PPIs) cover a very wide range of biological functions and consequently have become one of the favourite targets for new therapeutic strategies. PPIs are strongly characterised by an intricate and dynamic network of surface interactions occurring between two or more proteins. Because of the complexity of these interactions, many strategies have been applied with the aim to find selective modulators for a specific protein-protein complex. During the last decade, fragment-based approaches have served many drug discovery programs with an impressive increment of contributions, gaining a remarkable role in PPIs modulators’ development. In this review, we detail the successful fragment-to-clinical candidate evolutions related to PPI modulation. An overview on the physico-chemical properties of both fragment hits and lead compounds will be presented together with a statistical analysis of their distribution

Clinical candidates modulating protein-protein interactions:the fragment-based experience

\u3cp\u3eProtein-protein interactions (PPIs) cover a very wide range of biological functions and consequently have become one of the favourite targets for new therapeutic strategies. PPIs are strongly characterised by an intricate and dynamic network of surface interactions occurring between two or more proteins. Because of the complexity of these interactions, many strategies have been applied with the aim to find selective modulators for a specific protein-protein complex. During the last decade, fragment-based approaches have served many drug discovery programs with an impressive increment of contributions, gaining a remarkable role in PPIs modulators’ development. In this review, we detail the successful fragment-to-clinical candidate evolutions related to PPI modulation. An overview on the physico-chemical properties of both fragment hits and lead compounds will be presented together with a statistical analysis of their distribution.\u3c/p\u3