1. Antimicrobial macrozones interact with biological macromolecules via two-site binding mode of action: Fluorimetric, NMR and docking studies.
- Author
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Jednačak T, Mikulandra I, Smokrović K, Hloušek-Kasun A, Kapustić M, Delaš K, Piantanida I, Jurković M, Bertoša B, Zangger K, and Novak P
- Subjects
- Binding Sites, Molecular Structure, Serum Albumin, Bovine chemistry, Serum Albumin, Bovine metabolism, Thiosemicarbazones chemistry, Thiosemicarbazones pharmacology, Structure-Activity Relationship, Ribosomes metabolism, Ribosomes drug effects, Dose-Response Relationship, Drug, Animals, Cattle, Azithromycin pharmacology, Azithromycin chemistry, Azithromycin metabolism, Molecular Docking Simulation, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry, Microbial Sensitivity Tests, Escherichia coli drug effects, Fluorometry, Magnetic Resonance Spectroscopy
- Abstract
Macrozones are novel conjugates of azithromycin and thiosemicarbazones, which exhibit very good in vitro antibacterial activities against susceptible and some resistant bacterial strains thus showing a potential for further development. A combination of spectrometric (fluorimetry, STD and WaterLOGSY NMR) and molecular docking studies provided insights into atomic details of interactions between selected macrozones and biological receptors such as E. coli ribosome and bovine serum albumin. Fluorimetric measurements revealed binding constants in the micro-molar range while NMR experiments provided data on binding epitopes. It has been demonstrated that both STD and WaterLOGSY gave comparable and consistent results unveiling atoms in intimate contacts with biological receptors. Docking studies pointed towards main interactions between macrozones and E. coli ribosome which included specific π - π stacking and hydrogen bonding interactions with thiosemicarbazone part extending down the ribosome exit tunnel. The results of the docking experiments were in fine correlation with those obtained by NMR and fluorimetry. Our investigation pointed towards a two-site binding mechanism of interactions between macrozones and E. coli ribosome which is the most probable reason for their activity against azithromycin-resistant strains. Much better activity of macrozone-nickel coordinated compound against E. coli ribosome compared to other macrozones has been attributed to the higher polarity which enabled better bacterial membrane penetration and binding of the two thiosemicarbazone units thus additionally contributing to the overall binding energy. The knowledge gained in this study should play an important role in anti-infective macrolide design in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)
- Published
- 2024
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