|
|
The mechanism of action of phage tail-like bacteriocins on target cells and artificial membrane systems.
Hryzáková, Klára ; Fišer, Radovan (advisor) ; Ulrych, Aleš (referee)
Fonticins are phage tail-like bacteriocins produced by gram-negative bacterium Pragia fontium from the family Enterobacteriaceae. Phage tail-like bacteriocins can be divided into two different families: flexible ones (F-type) and contractile particles (R-type). Pragia fontium produces R-type particles that adsorb on the surface of sensitive bacterial cell and form pores probably during the contraction using mechanism similar to Type VI Secretion System. The pore-forming activity of fonticins was tested in vivo using bacterial cells. It was also characterized in vitro on artificial lipid membranes. On Black Lipid Membranes fonticins create large channels into the membranes; single channel conductance (G) is about two times higher than single channel conductance of well known α-hemolysine produced by Staphylococcus aureus. Further, we tested the voltage-dependent blocking of fonticin pores by native and unfolded proteins, dsDNA, ssDNA, polyethylene glycol and diamond nanoparticles. The rigid structure of fonticin nanotube in combination with constant conductivity makes it a promising device for analysing the size and shape of nanoparticles and large macromolecules. Key words: fonticin, bacteriocine, nanopore, Pragia fontium, blocking, pore-forming activity, black lipid membranes.
|
|
|
The role of Spr1851 protein Streptococcus pneumoniae in cell division
Jarošová, Václava ; Ulrych, Aleš (advisor) ; Seydlová, Gabriela (referee)
The role of Spr1851 protein Streptococcus pneumoniae in cell division Human extracellular pathogen S. pneumoniae encodes unique serin/threonine protein kinase of Eucaryotic type StkP and its cognate phosphatase PhpP. This kinase affects number of cellular processes including virulence, competence, cell division and cell wall synthesis by phosphorylating its substrates. Hypothetical protein Spr1851 named Jag was identified as a new StkP substrate in the membrane fraction by comparing the wild-type phosphoproteomes with StkP deleted strain. This protein consists of three domains and an interdomain region that contains T89 phosphorylation site. There is a Jag_N domain with an unknown function at the N-terminus. The C-terminus contains two domains - KH and R3H, which are highly conserved and their expected function is binding of nucleic acid. The main aim of this work is to explain the function of Jag protein, to determine the effect of individual domains on the phenotype and the localization of the protein and to determine the role of phosphorylation on T89. The results confirm that Jag protein could play a role in cell division or cell wall synthesis. Furthermore, the results indicate that the Jag_N domain is essential for the localization of the protein into the membrane, whereas the KH and R3H domains are...
|
|
|
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor
Ulrych, Aleš
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor WD-40 domains, also known as beta-transducin repeats, are highly conserved repeating amino acid units, which are found in a wide variety of eukaryotic proteins that have a range of different functions. In the late 1990s, the first WD-40 containing proteins were identified in prokaryotes, however the knowledge about their function is scarce. Streptomyces coelicolor is a gram-positive bacterium with complicated morphological and physiological differentiation in the course of its life cycle. The genome of Streptomyces coelicolor encodes 6 potential genes encoding proteins with WD-repeat motifs. To determine the function of two of these WD-40 genes (wdpB and wdpC), the deletion replacement mutants in both genes were prepared. Both mutants exhibited medium-dependent phenotypes, which are markedly evident on modified R3 plates. Phenotypic studies revealed that deletion of wdpB gene resulted in substantial reduction of aerial hyphae formation and reduced production of undecylprodigiosin. In addition, the hyphae of ΔwdpB mutant were unusually branched and showed the signs of precocious lysis. Delayed spore-containing hyphae were irregularly septated....
|
|
|
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor
Ulrych, Aleš ; Branny, Pavel (advisor) ; Pátek, Miroslav (referee) ; Španová, Alena (referee)
The pleiotropic effect of WD-40 domain containing proteins on cellular differentiation and production of secondary metabolites in Streptomyces coelicolor WD-40 domains, also known as beta-transducin repeats, are highly conserved repeating amino acid units, which are found in a wide variety of eukaryotic proteins that have a range of different functions. In the late 1990s, the first WD-40 containing proteins were identified in prokaryotes, however the knowledge about their function is scarce. Streptomyces coelicolor is a gram-positive bacterium with complicated morphological and physiological differentiation in the course of its life cycle. The genome of Streptomyces coelicolor encodes 6 potential genes encoding proteins with WD-repeat motifs. To determine the function of two of these WD-40 genes (wdpB and wdpC), the deletion replacement mutants in both genes were prepared. Both mutants exhibited medium-dependent phenotypes, which are markedly evident on modified R3 plates. Phenotypic studies revealed that deletion of wdpB gene resulted in substantial reduction of aerial hyphae formation and reduced production of undecylprodigiosin. In addition, the hyphae of ΔwdpB mutant were unusually branched and showed the signs of precocious lysis. Delayed spore-containing hyphae were irregularly septated....
|
guest ::
