The Structures and Binding Modes of Small-Molecule Inhibitors of Pseudomonas aeruginosa Elastase LasB

Abstract

Elastase B (LasB) is a zinc metalloprotease and a crucial virulence factor of Pseudomonas aeruginosa. As the need for new strategies to fight antimicrobial resistance (AMR) constantly rises, this protein has become a key target in the development of novel antivirulence agents. The extensive knowledge of the structure of its active site, containing two subpockets and a zinc atom, led to various structure-based medicinal chemistry programs and the optimization of several chemical classes of inhibitors. This review provides a brief reminder of the structure of the active site and a summary of the disclosed P. aeruginosa LasB inhibitors. We specifically focused on the analysis of their binding modes with a detailed representation of them, hence giving an overview of the strategies aiming at targeting LasB by small molecules.

Facile Production of the Pseudomonas aeruginosa Virulence Factor LasB in Escherichia coli for Structure‐Based Drug Design

“…Mutation of the catalytically essential amino acid His223 (zinc‐binding) to Tyr (pET‐26b‐LasB* PAO1H223Y ) resulted in the accumulation of the fusion protein prepro‐LasB, which supports the notion of autocatalytic processing of LasB (Figure S2A) [16] …”

“…Mutation of the catalytically essential amino acid His223 (zinc-binding) to Tyr (pET-26b-LasB* PAO1H223Y ) resulted in the accumulation of the fusion protein prepro-LasB, which supports the notion of autocatalytic processing of LasB (Figure S2A). [16] To determine if LasB expression in E. coli could provide the yields necessary for biological testing in the context of the development of LasB inhibitors, we attempted large-scale purification. Here, knowledge that LasB processing was autocatalytic proved essential: When the immobilized metal affinity chromatography (IMAC) column was loaded at room temperature and washed with lysis buffer, LasB* PAO1 eluted before a higher imidazole concentration was applied (Figure S3).…”

“…This poses a serious obstacle to attempts to exploit LasB for the development of antivirulence, or pathoblocker, compounds. LasB is a promising, validated target for drug development against serious PA infections, and high‐affinity inhibitors with outstanding selectivity over human off‐targets have very recently been reported [16–18] . From a medicinal chemistry perspective, extracellular targets are particularly attractive given that the drug candidates do not have to cross the Gram‐negative cell membrane to reach their site of action.…”

Diclofenac Sodium‐Encapsulated Poly(lactic‐co‐glycolic acid) Nanoparticles: A Non‐antibiotic Formulation to Attenuate the Proteolytic Activity of P. aeruginosa Clinical Isolates

“…Elastase B, also known as pseudolysin, is a zinc-dependent metalloendopeptidase which is associated with the major elastolytic activities, cleavage of host extracellular matrix proteins, such as collagen type III and IV, and epithelial disruption. [13,14] Moreover, by degrading several components of innate and adaptive immune defenses, it can interfere with the host immune system. Furthermore, elastase B plays a key role in the differentiation of pseudomonal biofilms, which can be crucial in infection establishment and drug resistance.…”

The dataset on the draft whole-genome sequences of two Pseudomonas aeruginosa strains isolated from urine samples of patients with urinary tract diseases

“…The RAST server predicted different types of secreted proteases involved in virulence, such as vibriolysin-like proteases and collagenases [ 8 , 9 ], in both the PA18 and PA23 genomes. Two crucial virulence factors, extracellular elastases AprA and LasB, which facilitate bacterial colonization and host tissue damage [ 10 ], were also represented in both genomes. Pyoverdine and pyochelin synthesis gene clusters (synthesis of siderophores – ferric ion chelators) were also predicted in both strains.…”