Luminescent Bacteria as Bioindicators in Screening and Selection of Enzymes Detoxifying Various Mycotoxins.

Interest in enzymes capable of neutralizing various mycotoxins is quite high. The methods used for the screening and selection of enzymes that catalyze the detoxification of mycotoxins should be sensitive and fast. However toxic compounds can be generated under the action of such enzymes.

The role of protein globule in firefly luciferase catalysis.

The important role of the dynamic structure of firefly luciferase in enzyme functioning is a subject of this literature review. Due to the domain alternation, the optimal configuration of the active site is created for each stage of the luciferin oxidation. The diversity of bioluminescence spectra is explained by the combined emission of several coexisting forms of electronically excited oxyluciferin.

firefly luciferase as a marker in bioluminescent immunoassays.

Chemical modification of the enzymes with biospecific macromolecules is used in various fields of biotechnology to impart new functions or improve their properties and is a fast and convenient way to get the final products. The preparation of highly active, stable, and functionally active conjugates of the thermostable luciferase through the NH-groups or free SH-groups of the enzyme with target molecules of different molecular weight (albumin, avidin from chicken eggs, antibodies, and progesterone) is described. The obtained conjugates were successfully tested as a reporter in bioluminescent immunoassay for the detection of the molecules and pathogens.

Bioluminescent test systems based on firefly luciferase for studying stress effects on living cells.

The bioluminescent luciferin-luciferase reaction is based on the oxidation of D-luciferin by oxygen in the presence of ATP and magnesium ions, catalyzed by firefly luciferase. The possibilities of using this reaction to study the influence of external effectors of a physical and chemical nature (temperature exposure, additions of drugs, membrane-active compounds, etc.) on living cells (prokaryotes and eukaryotes) are considered.

Application of Bioluminescent Methods to Study the Effect of the Membrane-active Antibiotic Colistin on Bacterial Cells.

For the first time, recombinant Escherichia coli cells expressing thermostable Luciola mingrelica firefly luciferase were used to study the effect of the membrane-active antibiotic colistin on live cells. Simple, fast, and highly sensitive bioluminescent methods were developed for measurement of luciferase activity and ATP concentration inside and outside E. coli cells incubated in a nutrient medium, or in saline.

Mechanisms of increased mitochondria-dependent necrosis in Wiskott-Aldrich syndrome platelets.

Wiskott-Aldrich syndrome (WAS) is associated with thrombocytopenia of unclear origin. We investigated real-time cytosolic calcium dynamics, mitochondrial membrane potential and phoszphatidylserine (PS) exposure in single fibrinogen-bound platelets using confocal microscopy. The WAS platelets had higher resting calcium levels, more frequent spikes, and their mitochondria more frequently lost membrane potential followed by PS exposure (in 22.

A Novel Streptavidin-luciferase Fusion Protein: Preparation, Properties and Application in Hybridization Analysis of DNA.

A streptavidin-luciferase fusion protein comprising the thermostable mutant form of firefly luciferase Luciola mingrelica and minimal core streptavidin was constructed. The streptavidin-luciferase fusion was mainly produced in a tetrameric form with high luciferase and biotin-binding activities. It was shown that fusion has the same K values for ATP and luciferin and the bioluminescence spectra as initial luciferase.

Firefly Luciferase-based Fusion Proteins and their Applications in Bioanalysis.

Firefly luciferase is widely used in molecular biology and bioanalytical systems as a reporter molecule due to the high quantum yield of the bioluminescence, availability of stable mutant forms of the enzyme with prescribed spectral characteristics and abundance of bacterial expression systems suitable for production of recombinant proteins in limitless quantities. In this review, we described fusion proteins of luciferase with biotin-binding domain and streptavidin, with proteins A and G, antibodies, with DNA- and RNA-binding proteins, as well as fusion proteins designed for BRET systems. The firefly luciferase-based fusion proteins are represented as an effective tool for the development of different bioanalytical systems such as (1) systems in which luciferase is attached to the surface of the target and the bioluminescence signal is detected from the specific complexes formed; (2) BRET-based systems, in which the specific interaction induces changes in the bioluminescence spectrum; and (3) systems that use modified or split luciferases, in which the luciferase activity changes under the action of the analyte.

Color-shifting mutations in the C-domain of L. mingrelica firefly luciferase provide new information about the domain alternation mechanism.

We identified three color-shifting mutations-Phe467Ser, Glu490Val, and Glu490Lys-in the C-domain of the wild-type recombinant L. mingrelica luciferase. These mutations had moderate effect on the specific activity and thermal stability of the enzyme but changed the pH-dependence of its bioluminescence spectra.

A simplified ATP method for the rapid control of cell viability in a freeze-dried BCG vaccine.

We propose a simple and cost-effective ATP method for controlling the specific activity of a freeze-dried BCG vaccine. A freeze-dried BCG vaccine is reconstituted with 1ml saline and incubated for 15min at room temperature and then for 1h at 37°C. The vaccine is then treated with apyrase to remove extracellular ATP.

The Bioluminescence Resonance Energy Transfer from Firefly Luciferase to a Synthetic Dye and its Application for the Rapid Homogeneous Immunoassay of Progesterone.

The sensitive BRET system for the homogeneous immunoassay of a low-molecular weight antigen was developed using progesterone as an example. Two thermostable mutants of the Luciola mingrelica firefly luciferase (Luc)-the "red" mutant with λmax.em = 590 nm (RedLuc) and the "green" mutant with λmax.

Bioluminescence assay for cell viability.

Theoretical aspects of the adenosine triphosphate bioluminescence assay based on the use of the firefly luciferin-luciferase system are considered, as well as its application for assessing cell viability in microbiology, sanitation, medicine, and ecology. Various approaches for the analysis of individual or mixed cultures of microorganisms are presented, and capabilities of the method for investigation of biological processes in live cells including necrosis, apoptosis, as well as for investigation of the dynamics of metabolism are described.

Bioanalytical systems based on bioluminescence resonance energy transfer using firefly luciferase.

Bioanalytical systems based on the Bioluminescence Resonance Energy Transfer (BRET) are widely used in fundamental biochemical studies, as well as for screening and analysis of biologically active compounds. The Renilla luciferase is the most often used energy donor in this system despite the fact that it has low bioluminescence quantum yield and demonstrates not so stable luminescence in time as the firefly luciferase. Moreover, the bioluminescence λmax is observed in the green region of the spectrum, which complicates signal recording in tissues during in vivo experiments.

Point mutations in firefly luciferase C-domain demonstrate its significance in green color of bioluminescence.

Firefly luciferase is a two-domain enzyme that catalyzes the bioluminescent reaction of firefly luciferin oxidation. Color of the emitted light depends on the structure of the enzyme, yet the exact color-tuning mechanism remains unknown by now, and the role of the C-domain in it is rarely discussed, because a very few color-shifting mutations in the C-domain were described. Recently we reported a strong red-shifting mutation E457K in the C-domain; the bioluminescence spectra of this enzyme were independent of temperature or pH.

Strategy of mutual compensation of green and red mutants of firefly luciferase identifies a mutation of the highly conservative residue E457 with a strong red shift of bioluminescence.

Bioluminescence spectra of firefly luciferases demonstrate highly pH-sensitive spectra changing the color from green to red light when pH is lowered from alkaline to acidic. This reflects a change of ratio of the green and red emitters in the bimodal spectra of bioluminescence. We show that the mutations strongly stabilizing green (Y35N) or red (H433Y) emission compensate each other leading to the WT color of firefly luciferase.

Bacillus subtilis alkaline phosphatase IV acquires activity only late at the stationary phase when produced in Escherichia coli. Overexpression and characterization of the recombinant enzyme.

The availability of recombinant monomeric alkaline phosphatase (AP) is highly desirable in analytical applications involving AP fusion proteins. The cobalt-dependant alkaline phosphatase IV from Bacillus subtilis (BSAP), which was reported to be strongly monomeric, was overexpressed in Escherichia coli using pET autoinduction system as a cytoplasmic protein without export signal sequence. After 1 day of growth, when the E.

Approaches to engineer stability of beetle luciferases.

Luciferase enzymes from fireflies and other beetles have many important applications in molecular biology, biotechnology, analytical chemistry and several other areas. Many novel beetle luciferases with promising properties have been reported in the recent years. However, actual and potential applications of wild-type beetle luciferases are often limited by insufficient stability or decrease in activity of the enzyme at the conditions of a particular assay.

Site-directed mutagenesis of cysteine residues of Luciola mingrelica firefly luciferase.

Single mutants (C62S, C62V, C86S, C146S, C164S), double mutants (C62/146S, C62/164S, C86/146S, C146/164S), and triple mutant C62/146/164S of the Luciola mingrelica firefly luciferase carrying C-terminal His(6)-tag were obtained on the basis of plasmid pETL7 by site-directed mutagenesis. Bioluminescence and fluorescence spectra were not altered by the introduced mutations. In the case of mutants C86S, C86/146S, C62/164S, and the triple mutant C62/146/164S, the K(m)(ATP) and K(m)(LH)(2) values were increased by a factor of ~1.

Thermostabilization of firefly luciferase by in vivo directed evolution.

Firefly luciferase is widely used in a number of areas of biotechnology and molecular biology. However, rapid inactivation of wild-type (WT) luciferases at elevated temperatures often hampers their application. A simple non-lethal in vivo screening scheme was used to identify thermostable mutants of luciferase in Escherichia coli colonies.

Triple substitution G216N/A217L/S398M leads to the active and thermostable Luciola mingrelica firefly luciferase.

Insufficient thermal stability of firefly luciferases often limits their application in a wide range of fields. The substitution A217L is known to greatly increase thermal stability of many firefly luciferases. However, for Hotaria parvula firefly luciferase, that shares 98% degree of homology with Luciola mingrelica luciferase, the A217L mutation is known to dramatically decrease catalytic activity.

[Rapid bioluminescent antibiotic susceptibility assay].

Rapid testing of pathogen susceptibility to antibiotics is of great practical value for rational chemotherapy of pyoinflammatory deseases and postoperative complications of microbial etiology. The standard microbiological methods, i.e.

Random mutagenesis of Luciola mingrelica firefly luciferase. Mutant enzymes with bioluminescence spectra showing low pH sensitivity.

Most firefly luciferases demonstrate a strong pH-dependence of bioluminescence spectra. Gene region encoding first 225 residues of Luciola mingrelica luciferase was subjected to random mutagenesis, and four mutants with altered pH-sensitivity of bioluminescence spectra were isolated. F16L substitution showed distinctly lower pH-dependence of bioluminescence spectra, and Y35N,H and F16L/A40S substitutions resulted in the enzymes with bioluminescence spectra virtually independent from pH in the range of 6.

Improved bioluminescent assay of somatic cell counts in raw milk.

Somatic cell count (SCC) in milk is considered to be a valuable indicator of cow mastitis. For assessment of SCC in milk, the bioluminescent assay based on determination of ATP from somatic cells ([ATPsom]) in milk was proposed earlier. However, this assay is still not widely used in practice owing to lower reliability compared with conventional methods such as direct microscopy and flow cytometry.

Interaction of firefly luciferase with substrates and their analogs: a study using fluorescence spectroscopy methods.

The results of the author's laboratory on the interaction of Luciola mingrelica firefly luciferase with substrates and their analogs using both steady-state and time resolved fluorescence are reviewed. The contribution of fluorescence of Trp and Tyr residues of the protein to its intrinsic fluorescence spectrum was estimated. Studies of quenching of Trp and Tyr fluorescence by luciferin and ATP allowed one to determine binding constants of the luciferase with substrates and to show that the binding of one substrate to the luciferase decreases the affinity of the enzyme for the other one.

Quenching of the fluorescence of Tyr and Trp residues of firefly luciferase from Luciola mingrelica by the substrates.

Luciferase of the firefly Luciola mingrelica is characterized by fluorescence of not only the unique Trp residue (lambda(em) = 340 nm), but also that of Tyr residues (lambda(em) = 308 nm). Quenching of the intrinsic fluorescence of the luciferase by its substrates luciferin and ATP (AMP) has been studied. Luciferin (LH2) quenches Trp fluorescence more efficiently than the fluorescence of Tyr residues.