Inhibiting the copper efflux system in microbes as a novel approach for developing antibiotics

Abstract

Five out of six people receive at least one antibiotic prescription per year. However, the ever-expanding use of antibiotics in medicine, agriculture, and food production has accelerated the evolution of antibiotic-resistant bacteria, which, in turn, made the development of novel antibiotics based on new molecular targets a priority in medicinal chemistry. One way of possibly combatting resistant bacterial infections is by inhibiting the copper transporters in prokaryotic cells. Copper is a key element within all living cells, but it can be toxic in excess. Both eukaryotic and prokaryotic cells have developed distinct copper regulation systems to prevent its toxicity. Therefore, selectively targeting the prokaryotic copper regulation system might be an initial step in developing next-generation antibiotics. One such system is the Gram-negative bacterial CusCFBA efflux system. CusB is a key protein in this system and was previously reported to play an important role in opening the channel for efflux via significant structural changes upon copper binding while also controlling the assembly and disassembly process of the entire channel. In this study, we aimed to develop novel peptide copper channel blockers, designed by in silico calculations based on the structure of CusB. Using a combination of magnetic resonance spectroscopy and various biochemical methods, we found a lead peptide that promotes copper-induced cell toxicity. Targeting copper transport in bacteria has not yet been pursued as an antibiotic mechanism of action. Thus, our study lays the foundation for discovering novel antibiotics.

The Advantages of EPR Spectroscopy in Exploring Diamagnetic Metal Ion Binding and Transfer Mechanisms in Biological Systems

“…In this study, a nanomolar concentration of the protein was studied by EPR spectroscopy, which is also applicable for in-vivo research [80,108]. In addition, the combination of several techniques, such as microscopy [103,109], copper uptake experiments using 64 Cu [110], UV-Vis and NMR [13,111], can provide a better and more complete picture on Cu-related biological processes.…”

Advances in Understanding of the Copper Homeostasis in Pseudomonas aeruginosa

“…Combinatorial drug treatment is a common strategy in the fight against fast-evolving cancer [ 176 ]. Because bacteria are also fast evolving, it seems evident that a combinatorial drug treatment that additionally targets the copper homeostasis provides a promising strategy in the fight against multidrug resistant pathogens [ 177 ].…”

Dual Roles of the Conditional Exosomes Derived fromPseudomonas aeruginosaBiofilms: Promoting and Inhibiting Bacterial Biofilm Growth

“…Among them, eight proteins ( #1-#8 ) were exclusively present on the D-Exo surface, while two ( #9 and #10 ) were exclusively present on the G-Exo surface. Protein #9 on the G-Exo surface is involved in the sulfate transport system of bacteria, which is responsible for energy coupling to the transport system, while protein #10 belongs to the CusCFBA copper efflux system, which plays a crucial role in copper homeostasis within the bacteria [30]. With these important functional proteins on its surface, the G-Exo may enhance bacterial viability and promote cell growth under normal culture conditions through interactions with target bacterial cells.…”