An anion and small molecule inhibition study of the β-carbonic anhydrase from Staphylococcus aureus

Abstract

Pathogenic bacteria resistant to most antibiotics, including the methicillin-resistant Staphylococcus aureus (MRSA) represent a serious medical problem. The search for new antiinfectives, possessing a diverse mechanism of action compared to the clinically used antibiotics, has become an attractive research field. S. aureus DNA encodes a β-class carbonic anhydrase, SauBCA. It is a druggable target that can be inhibited by certain aromatic and heterocyclic sulphonamides. Here we investigated inorganic anions and some other small molecules for their inhibition of SauBCA. The halides, nitrite, nitrate, bicarbonate, carbonate, bisulphite, sulphate, stannate, and N,N -diethyldithiocarbamate were submillimolar SauBCA inhibitors with K I s in the range of 0.26 − 0.91 mM. The most effective inhibitors were sulfamide, sulfamate, phenylboronic acid, and phenylarsonic acid with K I s of 7 − 43 µM. Several interesting inhibitors detected here may be considered lead compounds for the development of even more effective derivatives, which should be investigated for their bacteriostatic effects.

The combination of diethyldithiocarbamate and copper ions is active against Staphylococcus aureus and Staphylococcus epidermidis biofilms in vitro and in vivo

“…The concentrations of DDC and Cu 2+ play an important role in the proposed mode of action for the antibacterial activity of DDC-Cu 2+ . The mechanism of DDC can in part be explained by inhibition of the S. aureus carbonic anhydrase (Urbanski et al, 2021) and the chelation and extraction of required metal cofactors, including Cu 2+ from metallo-enzymes, such as superoxide dismutase, rendering bacteria more susceptible to oxidative stress (Frazier et al, 2019). In addition, at high levels Cu 2+ is toxic by the generation of reactive oxygen species through the Cu + /Cu 2+ redox cycle and by competing with other metals at the enzymatic binding sites, leading to the inactivation and oxidation of free thiol groups of various proteins (Baker et al, 2010;Dupont et al, 2011).…”

Staphylococcus aureus Genomes Harbor Only MpsAB-Like Bicarbonate Transporter but Not Carbonic Anhydrase as Dissolved Inorganic Carbon Supply System

“…From our results above, C0673 is in fact S. sciuri and not S. aureus , and hence the CA activity described was actually from S. sciuri . A very recent publication from the same group followed up on the study by reporting its inhibition profile of S. aureus CA with anions and other small molecules ( 12 ). The same recombinant protein described earlier was used in this study, meaning that the CA inhibition referred to S. sciuri and not S. aureus .…”

“…Since there are several publications in which an S. aureus -specific CA has been described and also studied ( 9 – 12 ), we investigated the question of whether a CA actually exists in S. aureus . Using BLASTp analyses, phenotypic characterization of mpsAB mutants, and the resistance studies to CA inhibitors, we demonstrate that there is no CA present in S. aureus .…”

Activation studies with amino acids and amines of a β-carbonic anhydrase fromMammaliicoccus (Staphylococcus) sciuripreviously annotated asStaphylococcus aureus(SauBCA) carbonic anhydrase

“…Among the pathogens investigated ultimately for the presence of druggable CAs, was Staphylococcus aureus , a bacterium known for its virulence and easy development of drug resistance to a variety of clinically used antibiotics 2 . In 2016 we identified in the NCBI database a sequence annotated as encoding for a β-CA in the genome of S. aureus , which we cloned, characterised and showed to be susceptible to inhibition with sulphonamides and anions, two of the most investigated classes of CAIs 2 .…”

“…Among the pathogens investigated ultimately for the presence of druggable CAs, was Staphylococcus aureus , a bacterium known for its virulence and easy development of drug resistance to a variety of clinically used antibiotics 2 . In 2016 we identified in the NCBI database a sequence annotated as encoding for a β-CA in the genome of S. aureus , which we cloned, characterised and showed to be susceptible to inhibition with sulphonamides and anions, two of the most investigated classes of CAIs 2 . This enzyme, denominated SauBCA, showed the typical behaviour of a bacterial β-CA, possessing a significant CO 2 hydrase catalytic activity, similar to those of other such enzymes described earlier in E. coli, M. tuberculosis , Salmonella enterica (serovar Typhimurium ), and many other pathogenic bacteria by us and other groups 1–5 .…”