As part of a programme of synthesizing and investigating the biological properties of new fluoroquinolone antibacterials and their targeting of topoisomerase IV from Streptococcus pneumoniae, we have solved the X-ray structure of the complexes of two new 7,8-bridged fluoroquinolones (with restricted C7 group rotation favouring tight binding) in complex with the topoisomerase IV from S. pneumoniae and an 18-base-pair DNA binding site-the E-site-found by our DNA mapping studies to bind drug strongly in the presence of topoisomerase IV (Leo et al. 2005 J. Biol. Chem. 280, 14 252-14 263, doi:10.1074/jbc.M500156200). Although the degree of antibiotic resistance towards fluoroquinolones is much lower than that of β-lactams and a range of ribosome-bound antibiotics, there is a pressing need to increase the diversity of members of this successful clinically used class of drugs. The quinolone moiety of the new 7,8-bridged agents ACHN-245 and ACHN-454 binds similarly to that of clinafloxocin, levofloxacin, moxifloxacin and trovofloxacin but the cyclic scaffold offers the possibility of chemical modification to produce interactions with other topoisomerase residues at the active site.
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http://dx.doi.org/10.1098/rsob.160157 | DOI Listing |
Chem Rec
January 2025
Bioinspired & Biomimetic Inorganic Chemistry Laboratory, Department of Chemistry, National Institute of Technology Calicut, Kozhikode, Kerala, 673601, India.
Direct methane to methanol conversion is a dream reaction in industrial chemistry, which takes inspiration from the biological methanol production catalysed by methane monooxygenase enzymes (MMOs). Over the years, extensive studies have been conducted on this topic by bioengineering the MMOs, and tailoring methods to isolate the MMOs in the active form. Similarly, remarkable achievements have been noted in other methane activation strategies such as the use of heterogeneous catalysts or molecular catalysts.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
The local electric field (LEF) plays an important role in the catalytic process; however, the precise construction and manipulation of the electric field microenvironment around the active site remains a significant challenge. Here, we have developed a supramolecular strategy for the implementation of a LEF by introducing the host macrocycle 18-crown-6 (18C6) into a cobalt phthalocyanine (CoPc)-containing covalent organic framework (COF). Utilizing the supramolecular interaction between 18C6 and potassium ion (K), a locally enhanced K concentration around CoPc can be built to generate a LEF microenvironment around the catalytically active Co site.
View Article and Find Full Text PDFChemSusChem
January 2025
Leiden University: Universiteit Leiden, Leiden Institute of Chemistry, Einsteinweg 55, Room number EE4.19, 2333 CC, Leiden, NETHERLANDS, KINGDOM OF THE.
Electrocatalysis in metal-organic frameworks is an interplay between the diffusion of charges, the intrinsic catalytic rate, and the mass-transport of reactants through the pores. Here a systematic study is carried out to investigate the role of the electrolyte nature and concentration on the oxygen reduction reaction (ORR) with the PCN-224(Co) MOF in aqueous electrolyte. It was found that the ORR activity is slightly influenced by the nature of the ions in solution, providing that the ionic strength is high enough to minimize the resistivity during the measurement.
View Article and Find Full Text PDFFront Parasitol
April 2024
Institut für Parasitologie, Biomedizinisches Forschungszentrum Seltersberg (BFS), Justus Liebig Universitaet Giessen, Giessen, Germany.
Introduction: Schistosomiasis has for many years relied on a single drug, praziquantel (PZQ) for treatment of the disease. Immense efforts have been invested in the discovery of protein kinase (PK) inhibitors; however, given that the majority of PKs are still not targeted by an inhibitor with a useful level of selectivity, there is a compelling need to expand the chemical space available for synthesizing new, potent, and selective PK inhibitors. Small-molecule inhibitors targeting the ATP pocket of the catalytic domain of PKs have the potential to become drugs devoid of (major) side effects, particularly if they bind selectively.
View Article and Find Full Text PDFFront Parasitol
October 2024
Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.
Background: Schistosomiasis is caused by infection with parasitic worms and affects more than 250 million people globally. The detection of schistosome derived circulating cathodic and anodic antigens (CCA and CAA) has proven highly valuable for detecting active infections, causing both intestinal and urinary schistosomiasis.
Aim: The combined detection of CCA and CAA was explored to improve accuracy in detecting infections.
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