Studies on the interactions of some small biomolecules with antibacterial drug benzethonium chloride and its active pharmaceutical ingredient ionic liquid (API-IL) benzethonium L-proline at varying temperatures

2018 ◽  
Vol 255 ◽  
pp. 530-540 ◽  
Author(s):  
Zhenning Yan ◽  
Limin Ma ◽  
Shuangxia Shen ◽  
Jinpeng Li
2017 ◽  
Author(s):  
Wei Lin ◽  
Kalyan Das ◽  
David Degen ◽  
Abhishek Mazumder ◽  
Diego Duchi ◽  
...  

Fidaxomicin is an antibacterial drug in clinical use in treatment ofClostridium difficilediarrhea1–2. The active pharmaceutical ingredient of fidaxomicin, lipiarmycin A3 (Lpm)1–4, is a macrocyclic antibiotic with bactericidal activity against Gram-positive bacteria and efflux-deficient strains of Gram-negative bacteria1–2, 5. Lpm functions by inhibiting bacterial RNA polymerase (RNAP)6–8. Lpm exhibits no cross-resistance with the classic RNAP inhibitor rifampin (Rif)7, 9and inhibits transcription initiation at an earlier step than Rif8–11, suggesting that the binding site and mechanism of Lpm differ from those of Rif. Efforts spanning a decade to obtain a crystal structure of RNAP in complex with Lpm have been unsuccessful. Here, we report a cryo-EM12–13structure ofMycobacterium tuberculosisRNAP holoenzyme in complex with Lpm at 3.5 Å resolution. The structure shows that Lpm binds at the base of the RNAP “clamp,” interacting with the RNAP switch region and the RNAP RNA exit channel. The binding site on RNAP for Lpm does not overlap the binding sites for other RNAP inhibitors, accounting for the absence of cross-resistance of Lpm with other RNAP inhibitors. The structure exhibits an open conformation of the RNAP clamp, with the RNAP clamp swung outward by ~17° relative to its position in catalytically competent RNAP-promoter transcription initiation complexes, suggesting that Lpm traps an open-clamp conformational state. Single-molecule fluorescence resonance energy transfer14experiments confirm that Lpm traps an open-clamp conformational state and define effects of Lpm on clamp opening and closing dynamics. We propose that Lpm inhibits transcription initiation by trapping an open-clamp conformational state, thereby preventing simultaneous engagement of transcription initiation factor σ regions 2 and 4 with promoter -10 and -35 elements. The results provide information essential to understanding the mode of action of Lpm, account for structure-activity relationships of known Lpm analogs, and suggest modifications to Lpm that could yield new, improved Lpm analogs.


2021 ◽  
Author(s):  
Edris Bazrafshan ◽  
Amin Allah Zarei ◽  
Leili Mohammadi ◽  
Muhammad Nadeem Zafar ◽  
Maryam Foroughi ◽  
...  

Abstract Tetracycline (TCy) belongs to PPCPs is such an widely used antibacterial drug, which is discharged from urban wastewater treatment plants or agricultural effluents. Due to low metabolism, poor absorption, overuse, and misuse, TCy is considered as threat to environmental and its removal from waste-water is vital. In this research, a novel ionic liquid modified magnetic activated carbon nanocomposite (IL@mAC) was synthesized, characterized, and the adsorption efficiency of IL@mAC for removal of TCy was investigated under different operational parameters of pH (3–11); dose of IL@mAC (0.01–0.1 g/50 mL); reaction time (30–240 min), and initial TCy concentration (50-1500 mg/L). The IL@mAC characterization was done using XRD, VSM, SEM-EDX, BET, and FTIR. Results of equilibrium experiment showed that the highest removal efficiency (~ 98%) was obtained using 0.06 g of IL@mAC in 135 min at pH 7 and temperature 303 K. Considering the correlation coefficients (R2) for different adsorption models, it can be deduced that adsorption of TCy onto IL@mAC is better followed by Langmuir (0.9977) in comparison to Freundlich (0.9412), and Temkin (0.9536) models. Furthermore, Langmuir adsorption capacity was observed to be 666.7 mg/g. The regeneration study showed that IL@mAC retained around 85% TCy adsorption efficiency after 6th cycle. Finally, the present study indicates that the IL@mAC is of a high applicability and has extremely high adsorbent capacity to remove TCy from water compared to most of other benchmark adsorbents reported in literature.


2020 ◽  
Vol 115 ◽  
pp. 136-147 ◽  
Author(s):  
Tikai Zhang ◽  
Bin Sun ◽  
Jiangna Guo ◽  
Mengyao Wang ◽  
Hengqing Cui ◽  
...  

2015 ◽  
Vol 17 (37) ◽  
pp. 24108-24120 ◽  
Author(s):  
M. T. Viciosa ◽  
G. Santos ◽  
A. Costa ◽  
F. Danède ◽  
L. C. Branco ◽  
...  

It was demonstrated that the combination of the almost water insoluble active pharmaceutical ingredient (API) ibuprofen with the biocompatible 1-ethanol-3-methylimidazolium [C2OHMIM] cation of an ionic liquid (IL) leads to a highly water miscible IL-API with a solubility increased by around 5 orders of magnitude.


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