We have tested the entire Keio collection of close to 4,000 single-gene knockouts in Escherichia coli for increased susceptibility to one of seven different antibiotics (ciprofloxacin, rifampin, vancomycin, ampicillin, sulfamethoxazole, gentamicin, or metronidazole). We used high-throughput screening of several subinhibitory concentrations of each antibiotic and reduced more than 65,000 data points to a set of 140 strains that display significantly increased sensitivities to at least one of the antibiotics, determining the MIC in each case. These data provide targets for the design of "codrugs" that can potentiate existing antibiotics. We have made a number of double mutants with greatly increased sensitivity to ciprofloxacin, and these overcome the resistance generated by certain gyrA mutations. Many of the gene knockouts in E. coli are hypersensitive to more than one antibiotic. Together, all of these data allow us to outline the cell's "intrinsic resistome," which provides innate resistance to antibiotics.
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http://dx.doi.org/10.1128/JB.01982-07 | DOI Listing |
J Pept Sci
March 2025
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
Fluorescent probes are widely used in cellular imaging and disease diagnosis. Acting as substitute carriers, fluorescent probes can also be used to help transport drugs within cells. In this study, commonly used fluorophores, TAMRA (5-carboxytetramethylrhodamine), PBA (1-pyrenebutyric acid), NBD (nitrobenzoxadiazole), OG (Oregon Green), and CF (5-carboxyfluorescein) were conjugated with the dipeptide β-Ala-Lys, the peptide moiety of the well-established peptide transporter substrate β-Ala-Lys(AMCA) (AMCA: 7-amino-4-methyl-coumarin-3-acetic acid) by modifying it with respect to side-chain length and functional end groups.
View Article and Find Full Text PDFProtein Sci
February 2025
Cell Physiology and Molecular Biophysics Department, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas, USA.
Purifying membrane proteins has been the limiting step for studying their structure and function. The challenges of the process include the low expression levels in heterologous systems and the requirement for their biochemical stabilization in solution. The human voltage-gated proton channel (hH1) is a good example of that: the published protocols to express and purify hH1 produce low protein quantities at high costs, which is an issue for systematically characterizing its structure and function.
View Article and Find Full Text PDFNat Commun
January 2025
Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.
Recalcitrant bacterial infections can be caused by various types of dormant bacteria, including persisters and viable but nonculturable (VBNC) cells. Despite their clinical importance, we know fairly little about bacterial dormancy development and recovery. Previously, we established a correlation between protein aggregation and dormancy in Escherichia coli.
View Article and Find Full Text PDFBiochemistry (Mosc)
December 2024
National Research Centre "Kurchatov Institute", Moscow, 123182, Russia.
Bacterial and viral RNA polymerases are promising targets for the development of new transcription inhibitors. One of the potential blockers of RNA synthesis is 7,8-dihydro-8-oxo-1,-ethenoadenine (oxo-εA), a synthetic compound that combines two adenine modifications: 8-oxoadenine and 1,-ethenoadenine. In this study, we synthesized oxo-εA triphosphate (oxo-εATP) and showed that it could be incorporated by the RNA-dependent RNA polymerase of SARS-CoV-2 into synthesized RNA opposite template residues A and G in the presence of Mn ions.
View Article and Find Full Text PDFBiochemistry (Mosc)
December 2024
Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
Taking into account involvement of the RNA-binding proteins in regulation of activity of poly(ADP-ribose) polymerase 1 (PARP1), a key factor of DNA repair, the effect of the intrinsically disordered protein Sam68 (Src-associated substrate during mitosis of 68 kDa) on catalytic activity of this enzyme was studied. Plasmid containing coding sequence of the Sam68 protein was obtained. Using the obtained construct, conditions for the Sam68 expression in cells were optimized and procedure for protein purification was developed.
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