WhiA transcription factor provides feedback loop between translation and energy production in a genome-reduced bacterium.

Introduction: WhiA is a conserved protein found in numerous bacteria. It consists of an HTH DNA-binding domain linked with a homing endonuclease (HEN) domain. WhiA is one of the most conserved transcription factors in reduced bacteria of the class Mollicutes.

Features of the DNA Escherichia coli RecN interaction revealed by fluorescence microscopy and single-molecule methods.

The SOS response is a condition that occurs in bacterial cells after DNA damage. In this state, the bacterium is able to reсover the integrity of its genome. Due to the increased level of mutagenesis in cells during the repair of DNA double-strand breaks, the SOS response is also an important mechanism for bacterial adaptation to the antibiotics.

SulA does not sequester FtsZ in Escherichia coli cells during the SOS response.

In Escherichia coli, the SulA protein is synthesized during the SOS response to arrest cell division. Two possible models of SulA action were proposed: the sequestration and the capping. In current paper, to clarify which model better reflects the SulA effect on cell division upon the SOS response, the FtsZ/SulA ratio was estimated inside cells based on fusion of both FtsZ and SulA to fluorescent protein mNeonGreen.

Two-Photon Excited Fluorescence of NADH-Alcohol Dehydrogenase Complex in a Mixture with Bacterial Enzymes.

Thorough study of composition and fluorescence properties of a commercial reagent of active equine NAD-dependent alcohol dehydrogenase expressed and purified from has been carried out. Several experimental methods: spectral- and time-resolved two-photon excited fluorescence, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fast protein liquid chromatography, and mass spectrometry were used for analysis. The reagent under study was found to contain also a number of natural fluorophores: free NAD(P)H, NADH-alcohol dehydrogenase, NADPH-isocitrate dehydrogenase, and pyridoxal 5-phosphate-serine hydroxymethyltransferase complexes.

Protealysin Targets the Bacterial Housekeeping Proteins FtsZ and RecA.

synthesizes the intracellular metalloprotease protealysin. This work was aimed at searching for bacterial substrates of protealysin among the proteins responsible for replication and cell division. We have shown that protealysin unlimitedly cleaves the SOS response protein RecA.

A new insight into RecA filament regulation by RecX from the analysis of conformation-specific interactions.

RecA protein mediates homologous recombination repair in bacteria through assembly of long helical filaments on ssDNA in an ATP-dependent manner. RecX, an important negative regulator of RecA, is known to inhibit RecA activity by stimulating the disassembly of RecA nucleoprotein filaments. Here we use a single-molecule approach to address the regulation of () RecA-ssDNA filaments by RecX () within the framework of distinct conformational states of RecA-ssDNA filament.

Single-molecule characterization of compressed RecA nucleoprotein filaments.

RecA is a central enzyme of homologous recombination in bacteria, which plays a major role in DNA repair, natural transformation and SOS-response activation. RecA forms nucleoprotein filaments on single-stranded DNA with a highly conserved architecture that is also shared by eukaryotic recombinases. One of the key features of these filaments is the ability to switch between stretched and compressed conformations in response to ATP binding and hydrolysis.

SulA is able to block cell division in Escherichia coli by a mechanism different from sequestration.

The SOS response is considered to be an extremely important feature of bacterial cells. It helps them to survive bad times, including helping to develop resistance to antibiotics. The SOS response blocks the cell division.

New insights into FtsZ rearrangements during the cell division of Escherichia coli from single-molecule localization microscopy of fixed cells.

FtsZ - a prokaryotic tubulin homolog - is one of the central components of bacterial division machinery. At the early stage of cytokinesis FtsZ forms the so-called Z-ring at mid-cell that guides septum formation. Many approaches were used to resolve the structure of the Z-ring, however, researchers are still far from consensus on this question.

RECOVERY OF DIVISION PROCESS IN BACTERIAL CELLS AFTER INDUCTION OF SulA PROTEIN WHICH IS RESPONSIBLE FOR CYTOKINESIS ARREST DURING SOS-RESPONSE.

SOS-response is an important tool of bacteria intended to protect their genome and thereby allow them to survive under adverse conditions. Recently SOS-response is considered to enhance mutagenesis and thus help bacteria acquire antibiotic resistance. Due to high significance of this phenomena it seems to be important to investigate processes that allow bacteria to survive after SOS-response activation.

Temporal dynamics of methyltransferase and restriction endonuclease accumulation in individual cells after introducing a restriction-modification system.

Type II restriction-modification (R-M) systems encode a restriction endonuclease that cleaves DNA at specific sites, and a methyltransferase that modifies same sites protecting them from restriction endonuclease cleavage. Type II R-M systems benefit bacteria by protecting them from bacteriophages. Many type II R-M systems are plasmid-based and thus capable of horizontal transfer.

Deinococcus radiodurans RecA nucleoprotein filaments characterized at the single-molecule level with optical tweezers.

Deinococcus radiodurans can survive extreme doses of ionizing radiation due to the very efficient DNA repair mechanisms that are able to cope even with hundreds of double-strand breaks. RecA, the critical protein of homologous recombination in bacteria, is one of the key components of the DNA-repair system. Repair of double-strand breaks requires RecA binding to DNA and assembly of the RecA nucleoprotein helical filaments.

[NEW INFORMATION ABOUT THE STRUCTURES FORMED BY FtsZ PROTEIN IN ESCHERICHIA COLI CELLS DURING DIVISION PROCESS OBTAINED BY SINGLE-MOLECULE LOCALIZATION MICROSCOPY].

FtsZ--a bacterial tubulin homolog--is one of the key bacterial division proteins, forming a contractile Z-ring at the midcell of dividing bacteria. In this work immunofluorescent labeling was used in conjunction with single-molecule localization microscopy (SMLM) to visualize native structures formed by FtsZ protein in Escherichia coli cells. This approach allowed the reorganization of FtsZ structures during cytokinesis to be visualized step-by-step.