It is known that RecX is a negative regulator of RecA protein. We found that the mutant RecA D112R protein exhibits increased resistance to RecX protein comparatively to wild-type RecA protein in vitro and in vivo. Using molecular modeling we showed, that amino acid located in position 112 can not approach RecX closer than 25-28 angstroms. Thus, direct contact between amino acid and RecX is impossible. RecA D112R protein more actively competes with SSB protein for the binding sites on ssDNA and, therefore, differs from the wild-type RecA protein by dynamics of filamentation on ssDNA. On the other hand, after the replacement of ATP by dATP, the wild-type RecA protein, changing the dynamics of filamentation on ssDNA, also becomes more resistant to RecX. Based on these data it is concluded that the dynamics of filamentation has a great, if not dominant role in the stability of RecA filament to RecX relative to the role of RecA-RecX protein-protein interactions discussed earlier. We also propose an improved model of regulation of RecA by RecX protein, where RecA filament elongation along ssDNA is blocked by RecX protein on the ssDNA region, located outside the filament.
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BMC Microbiol
January 2025
University of Amsterdam, Swammerdam Institute of Life Sciences, Molecular Biology and Microbial Food Safety, Amsterdam, The Netherlands.
Background: Fluoroquinolones are indispensable antibiotics used in treating bacterial infections in both human and veterinary medicine. However, resistance to these drugs presents a growing challenge. The SOS response, a DNA repair pathway activated by DNA damage, is known to influence resistance development, yet its role in fluoroquinolone resistance is not fully understood.
View Article and Find Full Text PDFGut Microbes
December 2025
Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu, China.
Protein glycosylation has been considered as a fundamental phenomenon shared by all domains of life. In , glycosylation of flagellins A and B with pseudaminic acid have been rigorously confirmed and shown to be essential for flagella assembly and bacterial colonization. In addition to flagellins, several other proteins including RecA, AlpA/B, and BabA/B in have also been reported to be glycosylated and to be dependent on the lipopolysaccharide (LPS) biosynthetic pathway.
View Article and Find Full Text PDFNaunyn Schmiedebergs Arch Pharmacol
January 2025
Department of Chemistry, Faculty of Science, Cairo University, Giza, 12613, Egypt.
Piperazine-based compounds have garnered significant attention due to their notable biological and pharmacological activities, making them essential in fine chemical and pharmaceutical applications. In this study, we managed to synthesize a novel hybrid bis-cyanoacrylamide bearing the piperazine core via phenoxymethyl linker and incorporating sulphamethoxazole moiety. The novel compound was fully characterized using different spectral data including 1H-NMR, C-NMR, and FTIR spectroscopy.
View Article and Find Full Text PDFPhytomedicine
February 2025
Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100073, China. Electronic address:
Background: Adherence of Helicobacter pylori to the surface of the gastric mucosa is the initial and crucial step for its survival and colonization in the harsh conditions of the stomach. We had previously demonstrated that daphnetin has anti-adhesion effect.
Purpose: This study aims to explore the mechanisms of daphnetin to reduce H.
Nucleic Acids Res
January 2025
MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, No.866 Yuhangtang Road, 310058, Hangzhou, China.
Meiosis in mammalian oocytes is interrupted by a prolonged arrest at the germinal vesicle stage, during which oocytes have to repair DNA lesions to ensure genome integrity or otherwise undergo apoptosis. The FIRRM/FLIP-FIGNL1 complex dissociates RAD51 from the joint DNA molecules in both homologous recombination (HR) and DNA replication. However, as a type of non-meiotic, non-replicative cells, whether this RAD51-dismantling mechanism regulates genome integrity in oocytes remains elusive.
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