|
|
Structural characterization of a model heme-containing oxygen sensor
Tajovská, Eva ; Martínková, Markéta (advisor) ; Ryšlavá, Helena (referee)
One subgroup of hemoproteins are heme-based gas sensors, which are able to detect biatomic gas molecules in their immediate surroundings. Upon binding of a gas molecule to the heme iron in a sensor domain of these proteins or, conversely, upon its dissociation from the heme iron, the signal is then transmitted from the sensor domain to a functional domain and subsequent regulation of important cellular functions occurs. Understanding the regulatory mechanism of gas sensors is key to potentially manipulating their function. Such knowledge would then allow the use of heme-based gas sensors as therapeutic targets for the development of next-generation antibiotics, if we take into account their presence in pathological bacteria. The diploma thesis focuses on a model heme-based gas sensor, the oxygen sensor EcDOS from E. coli, and its apoform, EcDOS His77Ala. Both proteins were prepared by recombinant expression and purification, and subsequently spectrophotometrically characterized. Using gel permeation chromatography, the oligomeric states of EcDOS Fe(III), EcDOS Fe(II)-O2 and EcDOS His77Ala were determined under different conditions (different temperatures of protein incubation, presence of c-di-GMP substrate etc.). Furthermore, the structural dynamics of EcDOS Fe(III), EcDOS Fe(II)-O2 and EcDOS...
|
|
|
Biochemical characterization of a model heme sensor protein
Tajovská, Eva ; Martínková, Markéta (advisor) ; Jeřábek, Petr (referee)
Hemoproteins play a lot of important roles within the living organism. One of these being the sensor function - heme sensor proteins are able to detect the changing concentration of heme in organisms. Heme itself serves as a signalling molecule for these proteins. Heme-based gas sensor proteins use a biatomic gas molecule as a signalling molecule. Signal transduction begins once the gas molecule is bound to the heme molecule which is already tightly bound in the protein sensing domain. Both these types of signalling regulate a number of physiological processes in the prokaryotic and eukaryotic organisms. The theoretical part of the bachelor thesis summarizes recent scientific studies on heme sensor proteins, while the experimental part focuses on the properties of a specific model sensor hemoprotein. A direct oxygen sensor from E. coli (EcDOS) was selected as a model protein. Furthermore, the thesis deals with a truncated form of the EcDOS protein, an isolated sensor domain with a PAS structure (EcDOS-PAS). The experimental part aimed at expressing and isolating of both mentioned proteins from E. coli BL-21 (DE3) cells. Finally, both the EcDOS and EcDOS-PAS proteins were preliminarily characterised and their properties compared. The yield of the EcDOS-PAS was several times higher than the yield of...
|
guest ::
